Question 850410
Let x   - be Mina's sister age now
    x+7 - be Mina's age now

    x+10   - be Mina's sister age now
    x+17   - be Mina's age now

{{{x+10+x+17=61}}}
{{{2x=34}}}
{{{x=17}}}

Mina's sister is 17 yo and Mina is 24 yo.

Hope that helps!!

#Rda33