y varies jointly with p and q. When p = 7 and q = 2, y = 70. Find y when p = 8 and q = 4

Question

amistre64 · Answer

stop deleting your questions, its rude to those who are reading it and helping out.

anonymous · Answer

true!!

amistre64 · Answer

to vary jointly is code for multiplications:

y = pq is the setup for this

amistre64 · Answer

in order for the numbers to make any sense in this; we have to introduce a "constant" of variation that will control the situation

anonymous · Answer

y = 160

amistre64 · Answer

y = kpq ; or rather k = y/(pq) will be needed for it to work out

amistre64 · Answer

When p = 7 and q = 2, y = 70. 

k = 70/(7*2) = 70/14 = 35/7 = 5

Find y when p = 8 and q = 4

y = 5pq,  y = 5(8*4) = 5(32) = 160 if i see it right

anonymous · Answer

y=160