Question

If the average grade of an English class rose from 70 to 85, what is the approximate percent increase?

answer choices

The percent increase is 14%.
The percent increase is 17%.
The percent increase is 21%.
The percent increase is 35%.

Answer 1

85 - 70 = 15

15/70 = 0.21428571428

Round to .21

Move decimal over twice to the right

21%

Answer 2

The percent increase is 21%.

Explanation:

Given,

The original average grade = 70,

New average grade = 85,

Total changes in the average grade = New average grade - original average grade

= 85 - 70

= 15

Since,

`\text{The percentage increment in the grade}=\frac{\text{Total changes}}{\text{Original grade}}* 100`

`=(15)/(70)* 100`

`=(1500)/(70)`

`=21.4285714\approx 21\%`

⇒ The approximate percent increase is 21 %.