Question 388958
Let their current ages be a, b, c, d. We have (a+10) + (b+10) + (c+10) + (d+10) = 100 --> a + b + c + d = 60. In 7 years their total will be


(a+7) + (b+7) + (c+7) + (d+7) = a + b + c + d + 28 = 60 + 28 = 88...strange...