Question

If p varies inversely as q and if p =4 when q =72 then find p when q =9

Answer 1

$<b>Step I :</b>$ $<u>Make an equation.</u>$

p ∝ ( 1 / q )



$<b>Step II :</b>$ $<u>Introduce K</u>$

After removing the sign ∝ , a constant, K will come.

p = K / q ...... ( 1 )



$<b>Step III :</b>$ $<u>Find the value of k</u>$

$<i> In First Situation</i>$, we have

p = 4, q = 72

Putting these values in ( 1 ), we get

4 = K / 72

k = 72 * 4 = 288



$<b>Step IV :</b>$ $<u>Find the value of p</u>$

$<i>In Second Situation:</i>$, we have

q = 9, k = 288

Putting this value in ( 1 ), we get

p = 288 / 9

p = 32.



Hence, $<u>the value of p is</u>$ $<u><I><b> 32.</b></u></I>$