Grace is filling her pool in the backyard with a hose that sprays 50 gallons/hour. She waited for 3 hours but the pool wasn't full, so she decides to add another hose that sprays 70 gallons/hour, and after 2 more hours the pool is full. How much water can Grace’s pool contain?
Let's think: In the first 3 hours the pool gets 50 gallons / hour x 3 hours = 150 gallons. With the addition of the other hose, the pool was filling with a rate of 50 gallons / hour + 70 gallons / hour = 120 gallons / hour. In the next 2 hours with both hoses the pool gets 120 gallons / hour x 2 hours = 240 gallons. The pool's total capacity is 240 gallons + 150 gallons = 390 gallons.. The answer is: 390.

Selene buys two instant cameras at $110 and three digital photo frames at $120 each. She gets a 5% discount on all the items she purchased. How much does she pay in all?
Let's think: Two instant camera cost 2 x $110 = $220. Three digital photo frames cost 3 x $120 = $360. Thus, the total amount is $220 + $360 = $580. So, Selena gets a discount of 5 / 100 x 580 = $29. Therefore, Selena pays a total of $580 - $29 = $551.. The answer is: 551.

Teresa orders 2 fancy ham and cheese sandwiches for $7.75 each at a local shop. While there, she decides to pick up some salami for $4.00, more brie which is three times the price of the salami, a 1/4 pound of olives that are $10.00 per pound, 1/2 pound of feta cheese that’s $8.00 a pound and another loaf of french bread that is $2.00. How much does she spend at the local shop?
Let's think: She orders 2 sandwiches that are $7.75 so they cost 2 * $7.75 = $15.50. The brie is three times more expensive than the $4.00 salami so the brie costs 3 * $4 = $12.00. She buys 1 / 4 pound of the olives that costs $10.00 a pound so they cost .25 * $10 = $2.50. She buys 1 / 2 pound of feta that costs $8.00 a pound so it costs .5 * $8 = $4.00. The salami is $4.00, the brie is $12.00, olives are $2.50 and the feta is $4.00 and the sandwiches are $15.50 for a total of $4 + $12 + $2.50 + $4 + $15.50 = $38.00. Adding the french bread gives $38.00 + $2.00 = $40.. The answer is: 40.

A charcoal grill burns fifteen coals to ash every twenty minutes of grilling. The grill ran for long enough to burn three bags of coals. Each bag of coal contains 60 coals. How long did the grill run?
Let's think:
The grill burned 3 * 60 = 180 coals. It takes 20 minutes to burn 15 coals, so the grill ran for 180 / 15 * 20 = 240 minutes.. The answer is: 240.