A 5-inch candle burns down in 4 hours. How far has it burned after 7 1/2 hours?

9 3/8 inches

Step-by-step explanation:

Inches of candle : hours it burned

= 5 inches : 4 hours

How far has it burned after 7 1/2 hours?

Let

x = how far it has burned (inches)

Inches of candle : hours it burned = x inches : 7 1/2 hours

Equate both ratios

5 inches : 4 hours = x inches : 7 1/2 hours

5/4 = x ÷ 7 1/2

5/4 = x ÷ 15/2

5/4 = x * 2/15

5/4 = 2x/15

Cross product

5 * 15 = 4 * 2x

75 = 8x

x = 75/8

x = 9 3/8 inches

x = how far it has burned (inches) = 9 3/8 inches

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

answer:

f(5/2) = 10/3

i hope this you!

1. 8

2. 9

3. 20

4. 3

5. 17

6. 2.2

7. 11.25

8. 1

9. 14

10. 2

step-by-step explanation:

thats the first half