Question

Xian and his cousin Kai both collect stamps. Xian has 64 stamps, and Kai has 76 stamps. The boys recently joined different stamp-collecting clubs. Xian's club will send him 20 new stamps per month. Kai's club will send him 16 new stamps per month. After how many months will Xian and Kai have the same number of stamps? How many stamps will each have?

Answer 1

Xian = 64+20m

Kai = 76+16m

set them equal

(m = months)

64 +20m = 76+16m

subtract 16 m from each side

64+4m = 76

subtract 64 from each side

4m = 12

m=3

in 3 months they will have the same number of stamps

64+20m = 64 +20(3) = 64+60 = 124

in 3 months they will have the same number of stamps, 124