Answered

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 :

[tex]J+M=27[/tex]
[tex]2J+M=40[/tex]

[tex]J=27-M[/tex]

[tex]2(27-M)+M=40[/tex]
[tex]54-2M+M=40[/tex]
[tex]54-M=40[/tex]
[tex]-M=-14[/tex]
[tex]M=14[/tex]

[tex]2J+14=40[/tex]
[tex]2J=26[/tex]
[tex]J=13[/tex]

John is 13 years old
Mary is 14 years old

apologiabiology
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