Question

Volunteers helped clean up 8.2 kg of trash in one neighborhood and 11 1/2 kg in another. They sent 1 1/4 kg to be recycled and threw the rest away. How many kilograms of trash did they throw away?

Answer 1

18.45 kg.

Explanation:

11 1/2 = 11.5 kg.

8.2 + 11.5 = 19.7 kg was the total trash collected.

Amount they threw away = 19.7 - 1 1/4

= 19.7 - 1.25

= 18.45 kg.

Answer 2

Answer:
`18.45\ kg` or
`18(9)/(20)\ kg`

Explanation:

We can convert from mixed numbers to decimal numbers:

`11(1)/(2)\ kg=(11+0.5)\ kg=11.5\ kg\\\\1(1)/(4)\ kg=(1+0.25)\ kg=1.25\ kg`

Since they cleaned up 8.2 kilograms of trash in one neighborhood and 11.5 kilograms in another neighborhood, the total trash they cleaned up was:

`Total=8.2\ kg+11.5\ kg\\\\Total=19.7\ kg`

We know that they sent 1.25 kilograms to be recycled. Then, in order to calculate how many kilograms of trash they threw away, we must subtract the total kilograms of trash they cleaned up and the kilograms they sent to be recycled.

Then:

`19.7\ kg-1.25\ kg=18.45\ kg` or
`18(9)/(20)\ kg`