Question

4. A varies directly as r. If A = 12, when r = 2, calculate:
a) the value of A, when r=5
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Answer 1

A varies directly to r means that A= kr
Substitute the given value : 12 = 2(k) —> k=6
Eqn : A=6r
When r=5,A= 6(5)= 30 thus A= 30

Answer 2

The value of A ,when r=5 then A = 14