Question

A pile of newspapers in Ms McGrath's art class was 17 3/4 inches high .Each Consecutive week,for the next 5 weeks,the height of the pile of newspapers increased by 8 7/12inches,What was the height ,in inches,of the pile after 3 weeks?

Answer 1

Answer:

The height will be 79 inches after 3 weeks.

Step-by-step explanation:

We are given that A pile of newspapers in Ms McGrath's art class was $17 \frac{3}{4} = \frac{71}{4}$inches high

We are also given that each Consecutive week,for the next 5 weeks,the height of the pile of newspapers increased by $8 \frac{7}{12} =\frac{103}{12}$inches

Now we are supposed to find What was the height ,in inches,of the pile after 3 weeks?

This situation is an AP

a =  $\frac{71}{4}$inches high

d =common difference = $\frac{103}{12}$inches

Formula of sum of first n terms  = $S_n=\frac{n}{2}(2a+(n-1)d)$

$S_{3}=\frac{3}{2}(2(\frac{71}{4})+(3-1)(\frac{103}{12}))$

$S_{3}=\frac{3}{2}(2(\frac{71}{4})+(3-1)(\frac{103}{12}))$

$a_{3}=79$

Hence the height will be 79 inches after 3 weeks.