Aladin_Baniel_GE-1B
EXERCISE VI. A
43. The length of a rectangle is 3 inches greater than its width. Its area is 70 square inches.
What are
its dimensions?
Step 1: Given
a rectangle with a length 3 inches greater than its width
it has an area of 70 square inches
Required: dimensions of the rectangle
Step 2: Assign variables
Let x = width of the rectangle
x + 3 = length of the rectangle
x+3
x
Step 3: Write an equation
Area of rectangle = (length)(width)
70 = (x + 3)(x)
Step 4: Solve
70 = (๐ฅ + 3)(๐ฅ)
70 = ๐ฅ 2 + 3๐ฅ
๐ฅ 2 + 3๐ฅ − 70 = 0
(๐ฅ + 10)(๐ฅ − 7) = 0
๐ฅ + 10 = 0 ๐ฅ − 7 = 0
๐ฅ = −10 ๐ฅ = 7
Step 5: State the answer
In this equation the answer cannot be negative therefore the length of the rectangle is 10
inches
and the width is 7 inches.
Step 6: Check
(7)(7 + 3) = 70
(7)(10) = 70
70 = 70 ๏
Aladin_Baniel_GE-1B
44. The diagonal of a rectangle is 2 inches greater than its length and 9 inches greater than its
width.
Find the dimensions of the rectangle.
Step 1: Given
a rectangle with a diagonal 2 inches greater than length and 9 inches greater than width
Required: dimensions of the rectangle
Step 2: Assign variables
Let x = diagonal of the rectangle
x – 2 = length of the rectangle
x – 9 = width of the rectangle
x- 2
x
x- 9
Step 3: write an equation
๐ฅ 2 = (๐ฅ − 2)2 + (๐ฅ − 9)2
Derived from Pythagorean Theorem
Step 4: Solve
๐ฅ 2 = (๐ฅ − 2)2 + (๐ฅ − 9)2
๐ฅ 2 = ๐ฅ 2 − 4๐ฅ + 4 + ๐ฅ 2 − 18๐ฅ + 81
๐ฅ 2 = 2๐ฅ 2 − 22๐ฅ + 85
๐ฅ 2 − 22๐ฅ + 85 = 0
(๐ฅ − 17)(๐ฅ − 5) = 0
๐ฅ − 17 = 0
๐ฅ−5=0
๐ฅ = 17
๐ฅ=5
๐๐๐๐ ๐๐ ๐กโ๐ ๐๐๐๐ก๐๐๐๐๐ = ๐๐ค
(15)(8) = 90
Step 5:State the answer
In this equation, the sides of the rectangle should not be negative, therefore, the
length of the
rectangle is 15 inches and the width is 8
inches of which the diagonal is 17 inches.
Step 6:Check
172 = 152 + 82
289 = 225 + 64
289 = 289 ๏
Aladin_Baniel_GE-1B
45. Find two consecutive positive integers whose product is 1332.
Step: Given
two consecutive integers
product is 1332
Required: the two integers
Step 2: Assign variables
Let x = first integer
x + 1 = second integer
Step 3: Write an equation
(x)(x + 1) = 1332
Step 4: Solve
(๐ฅ)(๐ฅ + 1) = 1332
๐ฅ 2 + ๐ฅ = 1332
2
๐ฅ + ๐ฅ − 1332 = 0
(๐ฅ + 37)(๐ฅ − 36) = 0
๐ฅ + 37 = 0 ๐ฅ − 36 = 0
๐ฅ = −37
๐ฅ = 36
Step 5: State the answer
In this equation the answer should not be negative, therefore the first integer is 36 and
the second integer is 37.
Step 6: Check
(36)(36 + 1) = 1332
(36)(37)=1332 ๏
Aladin_Baniel_GE-1B
47. Find two consecutive positive positive odd integers whose product is 783.
Step 1: Given
two consecutive odd integers
their product is 783
Required: the integers
Step 2: Assign variables
Let x = first integer
x + 2 = second integer
Step 3: Write an equation
(x)(x+2) = 783
Step 4: Solve
(๐ฅ)(๐ฅ + 2) = 783
๐ฅ 2 + 2๐ฅ = 783
2
๐ฅ + 2๐ฅ − 783 = 0
(๐ฅ − 27)(๐ฅ + 29) = 0
๐ฅ − 27 = 0
๐ฅ + 29 = 0
๐ฅ = 27
๐ฅ = −29
Step 5: State the answer
In this equation the answer cannot be negative, therefore the first integer is 27 and the
second integer is 29.
Step 6: Check
(27)(27+2) = 783
(27)(29) = 783
783 = 783 ๏
Aladin_Baniel_GE-1B
48. One number is ten more than another. Their product is 299. What are the numbers?
Step 1: Given
two numbers
the second number is ten more than the other
their product is 299
Required: the numbers
Step 2: Assign variables
Let x = first number
x + 10 = second number
Step 3: Write an equation
(x)(x+10) = 299
Step 4: Solve
(๐ฅ)(๐ฅ + 10) = 299
๐ฅ 2 + 10๐ฅ = 299
๐ฅ 2 + 10๐ฅ − 299 = 0
(๐ฅ − 13)(๐ฅ + 23) = 0
๐ฅ − 13 = 0 ๐ฅ + 23 = 0
๐ฅ = 13
๐ฅ = −23
Step 5: State the answer
In this equation the answer cannot be negative, therefore the first number 13 and the
second number is23
Step 6: Check
(13)(13+10) = 299
(13)(23) = 299
299 = 299 ๏
Aladin_Baniel_GE-1B
50. A tray with square base and a volume of 648 cubic inches is to be constructed from a square
sheet of tin by cutting 2-inch squares from the corners and bending up the sides. What size of
sheet of tin should be used?
Step 1: Given
a tray with a volume of 648
is made from a square sheet that is cut 2-inch square from its edge
Required: size of the square sheet
Step 2: Assign variables
Let x = side of the square base of the tray
x + 4 = side of the square sheet
2
x
2
2
2
x
x
2
2
2
x
X
Volume = 648cubic inch
2 inch
2
Step 3: Write an equation
(x)(x)(2) = 648
Step 4: Solve
(๐ฅ)(๐ฅ)(2) = 648
2๐ฅ 2 = 648
2๐ฅ 2
2
=
Side of square sheet = 18 + 4
= 22 inch
648
2
๐ฅ = √324
๐ฅ = 18
Step 5: State the answer
Therefore the size of the square sheet should be 22x22 suare inch.
Step 6: Check
(18)(18)(2) = 648
648 = 648 ๏
Aladin_Baniel_GE-1B
51. A rectangular sheet of cardboard is twice as long as it is wide. An open box having a capacity
of 168 cubic inches is made by cutting 3 inch squares from the cornes and banding up the sides
and ends. Find the dimensions of the cardboard.
Step 1: Given
a rectangular sheet of card board having a length of twice as long as its width
its cut 3 inch squares from its corners
making an open box that has a volume of 168 cubic inch
Required: dimensions of the rectangular sheet of cardboard
Step 2: Assign variables
Let x = width of the rectangular sheet of cardboard
2x = length of the rectangular sheet of cardboard
x – 6 = width of the box
2x – 6= length of the box
3
2x
3
3
3
x
3
2x-6
3
3
x-6
3inch
3
Volume=168 cubic inch
Step 3: Write an equation
(2x – 6)(x – 6)(3) = 168
Step 4: Solve
(2๐ฅ − 6)(๐ฅ − 6)(3) = 168
(2๐ฅ − 6)(3๐ฅ − 18) = 168
2
6๐ฅ − 36๐ฅ − 18๐ฅ + 108 = 168
6๐ฅ 2 − 54๐ฅ + 108 − 168 = 0
6๐ฅ 2 − 54๐ฅ − 60 = 0
(6๐ฅ − 60)(๐ฅ + 1) = 0
6๐ฅ − 60 = 0
๐ฅ+1=0
6๐ฅ
60
=6
๐ฅ = −1
6
๐ฅ = 10
Step 5: State the answer
In this equation the answer cannot be negative, therefore the width of the rectangular
sheet is 10inches and the length is 20inches and its area is 200-square inch.
Step 6: Check
(10 – 6)(20 – 6)(3)=168
(4)(14)(3)=168
168 = 168 ๏
Aladin_Baniel_GE-1B
52. A party of fishermen rented a boat for $240. Two of the men had to withdraw from the
party and, as a result, the share of each of the others was increased by $10. How many were in
the original party?
Step 1: Given
a group of fishermen rent a boat for $240
if two of them leave the group each payment will increase by $10
Required: number of fishermen in the original group
Step 2: Assign variables
Let x = number of original group of fishermen
Step 3: Write an equation
240
240
=
− 10
๐ฅ
๐ฅ−2
Step 4: Solve
240
๐ฅ
240
๐ฅ
240
๐ฅ
240
= ๐ฅ−2 − 10
=
=
240−10๐ฅ+20
๐ฅ−2
260−10๐ฅ
๐ฅ−2
240๐ฅ − 480 = −10๐ฅ 2
10๐ฅ 2 + 240๐ฅ − 260๐ฅ − 480 = 0
10๐ฅ 2 + 20๐ฅ − 480 = 0
(5๐ฅ + 30)(2๐ฅ − 16) = 0
5๐ฅ + 30 = 0
2๐ฅ − 16 = 0
5๐ฅ
−30
2๐ฅ
16
= 5
= 2
5
2
๐ฅ = −6
๐ฅ=8
Step 5: State the answer
In this equation the answer cannot be negative, therefore the number of the
original group of fishermen is 8.
Step 6: Check
240
Payment of original group = 8
= 30
240
When two of the men left = 6
= 40
40 – 30 = 10 ๏
Aladin_Baniel_GE-1B
53. A man drove 156 miles at a constant rate. If he had driven 5 miles per hour faster he would
have made the trip in 12 minutes less time. How fast did he drive?
Step 1: Given
A man drove 156 miles at a constant rate
He had driven 5 miles per hour faster
He would have made the trip in 12 minutes less time
Required: How fast did he drive?
Step 2: Assign values
Let 156 miles=distance
x mph=rate
156/x hours=time
Let 156 miles=distance
x+5 mph=rate
156 miles/x+5 mph=time
Step 3: Write an equation
Note that 12 minutes is equal to 1/5 hour…
156/x-(156/(x+5))=1/5 hour
Step 4:Solve
156
๐ฅ
156
1
− (๐ฅ+5) = 5 โ๐๐ข๐
๐ฅ(๐ฅ+5)
156(๐ฅ + 5) − 156 = 5
156 ∗ 5 ∗ 5 = ๐ฅ 2 + 5๐ฅ
๐ฅ 2 + 5๐ฅ − 3900 = 0
(๐ฅ − 60)(๐ฅ + 65) = 0
๐ฅ − 60 = 0 ๐ฅ + 65 = 0
๐ฅ = 60
๐ฅ = −65
Step 5:State the answer
In this equation the answer cannot be negative, therefore the man drove at the speed
of 60 mph
Step 6:Check
156
๐ฅ
156
60
156
1
− (๐ฅ+5) = 5 โ๐๐ข๐
−
156
60+5
=
1
5
156(65)−156(60)
(60)(65)
1
5
1
=5๏
1
=5
Aladin_Baniel_GE-1B
54. An airplane flying north at the rate of 240 miles per hour passed over a flying field at noon.
A second plane flying east at 200 miles per hour passed over the same field 5 minutes later.
When were they 250 miles apart?
Step 1: Given
an airplane flying north at the rate of 240mph passed a over a flying field
a second airplane flying east at the rate of 200mph passed over the same field 5 mins
later
Required: time in which they were 250 miles apart
Step 2: Assign variables and values
Let t= no. of minutes after 12 noon when the two planes were 250 miles apart
240/60 t=4t= no. of miles that the first airplane travel
200/60 t=3.33(t-5) = no. of miles that the second airplane travel
Step 3: Write an equation
200
(4๐ก)2 + ( 60 (๐ก − 5))2 = 2502
Step 4: Solve
200
2
(4๐ก)2 + ( 60 (๐ก − 5)) = 2502
16๐ก 2 + 11.1๐ก 2 − 111.1๐ก + 277.79 = 2502
27.1๐ก 2 − 111.1๐ก − 62 222.2 = 0
Solve for t using the quadratic equation
๐ก=
๐ก=
−๐±√๐ 2 −4๐๐
2๐
−(−111.1)±√(−111.1)2 −4(27.1)(62 222.2)
๐ก = 50
2(27.1)
๐ก = −45.9
Step 5: State the answer
Therefore the planes were 250 miles apart at 12:50 pm and 11:14 am.
Step 6: Check
2
(200)2 + (3.3333333(45)) = (250)2
40000 + 22500 = 62500
62500 = 62500 ๏