Seven people can paint a bridge in 15 days.

a) How long will it take 3 people to paint the bridge?

b) The bridge was painted in t days, write down an expression, in terms of t, for the number of people needed to paint the bridge

a) 3 people will need 35 days to paint the bridge

b) p=105/t

Step-by-step explanation:

a)

We have 7 people each one is to work 15 days, so the bridge needs a total of 7 (15) days of work

7 (15) = 105

Then we have 3 people each one is to work t days, altogether should do a total of 105 days of work

3 (t) = 105

Solve for t

t=35

b)

Substitute p for 3 in the second equation

p (t) = 105

Solve for p

p=105/t