SOLUTION: Sally is four times Linda’s age. In 10 years’ time the sum of their ages will be 75. Determine how old is Sally now.

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Question 1158958: Sally is four times Linda’s age. In 10 years’ time the sum of their ages will be 75.
Determine how old is Sally now.
Found 3 solutions by josgarithmetic, MathLover1, MathTherapy:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Let Sally's age be s.
Linda is s%2F4.

%28s%2B10%29%2B%28s%2F4%2B10%29=75
s%2Bs%2F4=55
4s%2Bs=220
highlight%28s=44%29

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

let Sally's age be x and Linda’s age y

if Sally is four times Linda’s age, we have
x=4y .....eq.1
if in 10 years’ time the sum of their ages will be 75, we have
%28x%2B10%29%2B%28y%2B10%29=75
x%2B10%2By%2B10=75
x%2By%2B20=75
x%2By=75-20
x%2By=55.......eq.2
substitute x from eq.1
4y%2By=55
5y=55
y=11
then
x=4y .....eq.1,substitute y
x=4%2A11
x=44

Sally is 44 years old now.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Sally is four times Linda’s age. In 10 years’ time the sum of their ages will be 75.
Determine how old is Sally now.
As their ages sum to 75 in 10 years' time, their ages now sum to 75 - 2(10) = 75 - 20 = 55 

Let Sally's age be S

Then Linda's is: S%2F4

We then get: matrix%281%2C3%2C+S+%2B+S%2F4%2C+%22=%22%2C+55%29

4S + S = 220 ------ Multiplying by LCD, 4

5S = 220

Sally, or