Question

A varies directly and A=8 when m=20 find A when m=15 and m when A=7​

Answer 1

Answer:

$A = 16$ -- (a)

$m = 17.5$ -- (b)

Step-by-step explanation:

Given

Variation: Direct

A = 8; m = 20

First, represent the variation.

$A\ \alpha\ \ m$

Represent as an equation

$A = km$

Make k, make the subject

$k = \frac{A}{m}$

A = 8; m = 20; So

$k = 8/20$

$k = 0.40$

When m = 20, we have:

$A = km$

$A = 0.40 * 40$

$A = 16$

When A = 7, we have:

$A = km$

$7 = 0.40 * m$

$m = \frac{7}{0.40}$

$m = 17.5$