1. Peter handed back the photo. "Your grandson, eh?" he commented. "How old is he now?" "I thought you'd ask," Mike chuckled. "Some years ago he was the square root of my age then, but that same number of years from now I'll be five times what he'll be." Surely you can solve that one!

Boy 12 years, Mike 70

Boy 11 years, Mike 67

Boy 9 years, Mike 64