
7 + 14 + 21 + ... + 105 =
= 7(1 + 2 + 3 + ... + 15)
= 7(15)(16)/2
= 840
Michael's present age is 53
Step-by-step
17-4=13
John is 13
than when John will be 49
u add 4 to 49
4+49=53
so Michael is 53 because he is 4 years older :)
Answer:
use geogebra app you can install it on your pc
Answer:
123
Step-by-step explanation: