Papa is putting new concrete on a driveway. The driveway is 30' x 10' x 9" thick. Concrete is measured by the cubic yard. One sack of dry cement mix costs $7.30, and it takes four sacks to mix up 1 cubic yard of concrete. How much will it cost?

Papa is putting new concrete on a driveway. The driveway is 30' x 10' x 9" thick. Concrete (a mixture of sand, gravel, and cement) is measured by the cubic yard. One sack of dry cement mix costs $7.30, and it takes four sacks to mix up 1 cubic yard of concrete. How much will it cost Mike to buy the cement?

1 Answer
Oct 6, 2017

Answer:

Assuming you can't buy one third of a sack of cement, it will cost $248.20

Explanation:

Since we are dealing with cubic yards let's convert our driveway measurements from feet to yards and inches to yards.

Remember #36# inches#=1# yard and #3# feet#=1# yard

So instead of #30# feet #xx##10# feet #xx# #9# inches

We get: #10# yards #xx##10/3# yards #xx# #1/4# yards

Multiplying these together we need: #25/3=8.bar(3)# cubic yards

If we multiply the amount we need by 4 we get how many sacks of dry cement are required:

#25/3*4=100/3=33.bar(3)# sacks

However you probably can't buy one third of a sack so round it up to 34 sacks.

Since each sack costs $7.30 we multiply the number of sacks by 7.3:

#34*7.3=248.2# which as a cash value equals $248.20.