Question

Lucy earned $400 and $550 in interest the last 2 years. Describe the average interest she should earn in each of the next 3 years so that her total earnings over the 5-year period are at least $2300.

Answer 1

The minimum average interest she should earn in each of the next 3 years is $450

Explanation:

Let

x -----> the average interest she should earn in each of the next 3 years

we know that

The sum of the amount earned over the 5-year period must be greater than or equal to $2,300

The inequality that represent this situation is

`400+550+3x \geq 2,300`

Solve for x

Combine like terms left side

`950+3x \geq 2,300`

subtract 950 both sides

`3x \geq 2,300-950`

`3x \geq 1,350`

Divide by 3 both sides

`x\geq \$450`

therefore

The minimum average interest she should earn in each of the next 3 years is $450