Michael spends a half hour adding water to his pool part of the time at a rate of 15 gallons per minute and the rest of the time at a rate of 9 gallons per minute. Let t be the time in minutes that he adds water at the faster rate write an algebraic expression to represent the total number of water added to the pool

24t + 270 gallons

Step-by-step explanation:

Given that :

Addition rate 1 = 15 gallons per minute

Addition rate 2 = 9 gallons per minute

Total time spent adding water = half an hour = 30 minutes = 0.5 hour

Time spent adding water at faster rate = t

Time spent addition water at slower rate = (30 - t)

Total number of water added to the pool :

Amount of water added = addition rate * time

Hence,

Amount of water added at faster rate :

(15 gal / min) * t = 15t gallons

Amount added at slower rate :

(9 gal / min) * (30 - t) = (270 - 9t) gallons

Total amount of water added to the pool:

15t gallons + (270 - 9t)gallons

15t + 270 + 9t

24t + 270 gallons

15.5

step-by-step explanation:

5

∑

n = 1

substitute n = 1, 2, 3, 4, 5 and sum the terms

= + + + 2² + 2³

= 0.5 + 1 + 2 + 4 + 8

= 15.5

answer is a

step-by-step explanation: