if twice the sons age is added to the fathers age, the sum is 75. but if twice the fathers age is added to the sons age, the sum is 120. find the age of father?
Answers
Answer:
55
Step-by-step explanation:
let x = son's age and y = father's age,
2x + y = 75
2y + x = 120
multiply the second equation by 2:
4y + 2x = 240
subtract the first equation from that
3y = 165
y = 55
Answer:
The son is 20 and the father is 50
Step-by-step explanation:
Son's age S
father's age F
2 different eauations:
Equation one: 2S+F=90
Equation two: 2F +S=120
Step 1) Solve Equation 1 for F:
2s+f=90
2s-2s+f=90-2s
0+f=90-2s
f=90-2s
Step 2) Substitute (90-2s) for f in Equation 2 and solve for s
2f+s=120 becomes:
2(90−2s)+s=120
(2⋅90)−(2⋅2s)+s=120
180−4s+s=120
180−4s+1s=120
180+(−4+1)s=120
180+(−3)s=120
180−3s=120
180−180−3s=120−180
0−3s=−60
−3s=−60
−3s/3=−60/−3
−3s−3=20
s=20
Step3) Substitute 20for s in the solution to the first equation at the end of Step 1 and calculate f:
f=90−2s becomes:
f=90−(2⋅20)
f=90-40
f=50
The son's age is 20 and the father's age is 50