Question

An automatic swing is designed to hold a baby who weighs at least 12 pounds but no more than 20 pounds. If a baby weighs 7.2 pounds at birth and gains 0.2 pounds each week, for what range of weeks will it be safe to put the baby in the swing? Write your answer in interval notation.

Answer 1

12 ≤ 0.2x + 7.2
4.8 ≤ 0.2x
x ≥ 24

20 ≥ 0.2x + 7.2
12.8 ≥ 0.2x
x ≤ 64
24 ≤ x ≤ 64

Answer 2

THis is how you do it setting up 2 different inequalities, but you might be able to do it using a compound inequality.

Answer 3

first we have to wait the baby grow to 12 pounds
it needs (12-7.2)/0.2=24 weeks
and till the baby to 20 pounds
it needs (20-12)/0.2=40 another weeks
so the range is 24~64

Answer 4

Do you get it?

Answer 5

yes thanks

Answer 6

You're welcome :)