Answer:
The two clubs will have the same number of members after 7 years
Explanation:
Let the number of years is x
∵ A chess club has 480 members but is losing 30 members each year
∵ The number of years = x
∴ The total members after x years = 480 - 30x ⇒ (1)
∵ A computer club has 130 members and is gaining 20 members per year
∵ The number of years = x
∴ The total members after x years = 130 + 20x ⇒ (2)
∵ The two clubs will have the same number of members after x years
→ Equate (1) and (2)
∴ 480 - 30x = 130 + 20x
→ Add 30x t both sides
∵ 480 - 30x + 30x = 130 + 20x + 30x
∴ 480 = 130 + 50x
→ Subtract 130 from both sides
∵ 480 - 130 = 130 - 130 + 50x
∴ 350 = 50x
→ Divide both sides by 50
∴ 7 = x
∴ The two clubs will have the same number of members after 7 years