geometry
posted by Olivia .
The ratio of two similar prisms is 2:5 the volume of the larger is 375cm3 if sand is being poured into the smaller prism at 3cm3 per second how many seconds will it tAke to fill the smaller prism?

2/5 = x/375
5x = 750
x = 150
150/3 = 50 seconds 
Find the volume of the smaller one by using a proportion. The volume is 150, and then just divide it by 3. Pretty simple once you get it, and your answer would be 50 sec.

I will assume you mean that the ratio of their corresponding sides is 2 : 5.
the volume of two similar figures is proportional to the cube of their sides
so V1/V2 = 2^3 / 5^3 = 8/125
V1/375 = 8/125
V1 = 24
so time to fill the larger = 375/3 = 125 seconds
time to fill the smaller = 24/3 = 8 seconds
If the two volumes are in the ratio of 2 : 5 then go with the two solutions by Ms. Sue and Shaniqua
(Can you see how important it is to clearly state your problem ?)