228k views
0 votes
D varies as R and S, and inversely as t. D=12, R=3, S=20, and t=5, find D when R=15, S=4 and t=8.

1 Answer

5 votes

Given:

D varies as R and S, and inversely as t.

D=12, R=3, S=20, and t=5

To find:

The value of D when R=15, S=4 and t=8.

Solution:

It is given that D varies as R and S, and inversely as t. So,


D\propto (RS)/(t)


D=(kRS)/(t) ...(i)

Where, k is the constant of proportionality.

We have, D=12, R=3, S=20, and t=5. Substituting these values in (i), we get


12=(k(3)(20))/(5)


12=12k


(12)/(12)=k


1=k

Substituting
k=1 in (i), we get the required equation.


D=((1)RS)/(t)


D=(RS)/(t)

We need to find D when R=15, S=4 and t=8. Substituting R=15, S=4 and t=8 in the above equation, we get


D=((15)(4))/(8)


D=(60)/(8)


D=7.5

Therefore, the required value of D is 7.5.

User Tilo
by
8.1k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories