Question

If 3 : 8 is equivalent to (2x + 13): 72, then what
is the value of x?

Answer 1

x = 7

Explanation:

3 : 8 can be expressed as the ratio
`\displaystyle {(3)/(8)}`

(2x + 13) : 72 can be expressed as the ratio:
`(2x + 13)/(72)`

Equating the two ratios:

`(3)/(8) = (2x + 13)/(72)`

Cross multiplying we get

`3 * 72 = (2x + 13) * 8\\\\3 * 72 = 2x(8) + 13(8)\\\\216 = 16x + 104`

Switch sides:
16x + 104 = 216

16x = 216 - 104

16x = 112

x = 112/16 = 7

Therefore x = 7

Answer 2

7

Explanation:

If 3 : 8 is equivalent to (2x + 13): 72, then what

is the value of x?

3 : 8 = (2x + 13) : 72

3×18−{(2x+13)×1/72}=0

38−{(2x+13)×1/72}=0

38−{1/36x+13/72}=0

−1/36x+7/36=0

(−1/36)⋅x+(7/36)=0

x=−(7/36)−1/36

x=7