Concrete is made by mixing cement, sand, and gravel in the ratio 5:9:13. How much cement
is nceded to make 324 ft of concrete?

60

Step-by-step explanation:

Sum the parts of the ratio, 5 + 9 + 13 = 27 parts

Divide the amount of concrete by 27 to find the value of one part of the ratio.

324 ÷ 27 = 12 ← value of 1 part of the ratio , thus

5 parts = 5 × 12 = 60 ← cement

9 parts = 9 × 12 = 108 ← sand

13 parts = 13 × 12 = 156 ← gravel

60 ft.

Step-by-step explanation

The fraction of cement on the concrete  

=  5 / (5+9+13)

= (5/27) * 324

= 5 * 12

= 60 ft.

the correct answer is d

hope this

$25

step-by-step explanation:

25 - 4.50 = 20.5

20.5 / 2 = 10.25

10.25 + 10 = 20.25

20.25 - 12.50 = 7.75

therefore the answer is $25 as shown as the first number.