The product of 2 numbers is 1575 and their quotient is ​$ \frac{9}{7} $​​. Then the sum of the numbers is

Question:
The product of 2 numbers is 1575 and their quotient is $ \frac{9}{7} $​​. Then the sum of the numbers is
a.   74
b.   78
c.   80
d.   90

Answer:
Let the numbers be x and y.
​$ \therefore xy=1575 $​ and ​$ \frac{x}{y}=\frac{9}{7} $​
​$ \therefore \frac{xy}{(\frac{x}{y})}=\frac{1575}{(\frac{9}{7})} $​
​$ \therefore y^2=1225 $​
​$ \therefore y=35 $​
Hence, ​$ x=45 $​
So, sum of the numbers
​$ =x+y $​
​$ =35+45 $​
​$ =80 $​