At a country concerts the ratio of the number of boys to the number of girls 2 to 7. if there are 250 more girls than boys how many boys are at the concerts.

Let B be the number of boys and G = number of girls:

B/G = 2/7 (given)

And

G = 250+B (given), then

B/G = B / (250+B) = 2/7

B / (250+B) = 2/7 → Cross multiplication:

7. B = 2 (250+B) → 7. B = 500 + 2. B

5. B = 500 And B = 500/5 And B = 100

Boys = 100 and Girls = 350

Proof: 100/350 = 10/35 = 2/7