Question

the ages of John and Mary total 27 years. Mary's age plus twice john's age is 40. how old is each person?

Answer 1

So
Jon's age=j
mary age=m


m+j=27
m+2 times j=40
m+2j=40
M+j=27
ssubtract j from both sides
m=27-j
subsitute 27-j for m
27-j+2j=40
27+j=40
subtract 27 fromboth sdies
j=13

subsitue
13+m=27
subtract 13
m=14

mary=14
john=13

Answer 2

$J+M=27$
$2J+M=40$

$J=27-M$

$2(27-M)+M=40$
$54-2M+M=40$
$54-M=40$
$-M=-14$
$M=14$

$2J+14=40$
$2J=26$
$J=13$

John is 13 years old
Mary is 14 years old