math
posted by kitty on .
the volume of a small balloon is 2 liters and a larger balloon is 5 liters. the small balloon is increased at a rate of 0.3 per sec. larger balloon is decreased at a rate of 0.12 liters per sec. after how many seconds will the two balloon have the same liters.

let the time taken be t seconds
2 + .3t = 5  .12t
.42t = 3
t = 3/.42 = 7.14 seconds
check:
after 7.14 seconds, volume of smaller balloon = 2 + 7.14(.3) = 4.14
after 7.14 seconds, volume larger ballon = 5  7.14(.12) = 4.14
OK then!