A + T = 165
A= amanda's grade
T= tim's grade
A = T +11
substitute A for T + 11 and you get
T+ 11 +T = 165
combine like terms:
2T + 11 = 165
subtract 11 from both sides:
2T= 154
divide both sides by 2
T = 77 (Tim's grade)
A= 77 +11
so: A= 88 (Amanda's grade)
check answer:
88 + 77 = 165!
Hope this helps!
