If r varies jointly as p and q and inversely as t, then how do you find an equation for r if r=6 when p=8, q=−3, and t=3?
1 Answer
Jul 30, 2017
Explanation:
"the initial statement is "rprop(pq)/tthe initial statement is r∝pqt
"to convert to an equation multiply by k the constant"to convert to an equation multiply by k the constant
"of variation"of variation
rArrr=(kpq)/t⇒r=kpqt
"to find k use the given condition"to find k use the given condition
r=6" when "p=8,q=-3" and "t=3r=6 when p=8,q=−3 and t=3
r=(kpq)/tr=kpqt
rArrkpq=rtlarrcolor(blue)" cross-multiplying"⇒kpq=rt← cross-multiplying
rArrk=(rt)/(pq)=(6xx3)/(8xx-3)=18/(-24)=-3/4⇒k=rtpq=6×38×−3=18−24=−34
rArr" equation is " color(red)(bar(ul(|color(white)(2/2)color(black)(r=-(3pq)/(4t)color(white)(2/2)|)))