Question

Needs equations to solve.
Laura's age is 3/4 of her sister Sara's and in 5 years it will be her 4/5. How old are the two sisters?

Answer 1

Answer:

Sara is 20 years old and Laura is 15 years old

Step-by-step explanation:

Let Sara's age be x years

Then Laura's age would be $\frac{3x}{4}$ years

After 5 years Sara's age would be (x+5) and Laura's age would be $(\frac{3x}{4}+5 )$

According to the questions

$\therefore(\frac{3x}{4}+5)=\frac{4(x+5)}{5}\\\\\implies(\frac{3x}{4}+5)=\frac{4x}{5}+4\\\\\implies5-4=\frac{4x}{5}-\frac{3x}{4}\\\\\implies1=\frac{16x-15x}{20}\\\\\implies20=16x-15x=x$

Therefore Sara's age would be 20 years then

Laura's age would be $\frac{20*3}{4}=15 years$