7. The sum of two consecutive multiples of 5 is 55. Find these multiples.
Solution:
Let the first multiple of 5 be x.
Then the other multiple of 5 will be x + 5 and their sum = 55
Therefore, x + x + 5 = 55
⇒ 2x + 5 = 55
⇒ 2x = 55 - 5
⇒ 2x = 50
⇒ x = 50/2
⇒ x = 25
Therefore, the multiples of 5, i.e., x + 5 = 25 + 5 = 30