Question

Jane had 275 stickers, which she gave to her friends. Each friend got five more stickers than the friend before. If the first friend got 5 stickers, how many friends got stickers from Jane?

Answer 1

Answer:

10 friends

Step-by-step explanation:

we know that

The formula of the sum is equal to

$sum=\frac{n}{2}[2a1+(n-1)d]$

where

a1 is the first term

n is the number of terms (number of friends)

d is the common difference in the arithmetic sequence

In this problem we have

$sum=275\ stickers$

$a1=5\ stickers$

$d=5$ ----> the common difference

substitute in the formula and solve for n

$275=\frac{n}{2}[2(5)+(n-1)(5)]$

$550=n[10+5n-5]\\ \\550=10n+5n^{2} -5n\\ \\5n^{2}+5n-550=0$

Solve the quadratic equation by graphing

The solution is n=10

see the attached figure

therefore

She had 10 friends who got stickers