Question

A small plant is 212 inches tall. How tall will it be in 3 weeks if it grows 34 inch each week? Which method will NOT give the correct number of inches?

Answer 1

Multiply
`2(1)/(2)` by
`3` and then add
`(3)/(4)`

Explanation:

we know that

using proportion

`((3/4))/(1)(in)/(week)=(x)/(3)(in)/(weeks) \\ \\x=3*(3/4)\\ \\x=9/4\ in`

Find the height of the plant in
`3` weeks

`2(1)/(2) +(9)/(4)=(5)/(2) +(9)/(4)\\ \\=(19)/(4)\ in`

therefore

The incorrect method is

Multiply
`2(1)/(2)` by
`3` and then add
`(3)/(4)`

because

`2(1)/(2)*3+(3)/(4)=(15)/(2)+(3)/(4)\\ \\=(33)/(4)\ in`