if 30% of a given number is45, whatis 80% of the given number

Question

A math problem that is a word problem that i need solved, if 30% of a given number is 45, what is 80% of the given number 

Answer 1

I always remember IS/OF = %/100.  So set up a ratio.  IS = 45, OF is unknown, % is 30.  Therefore, 45/x = 30/100.  Cross multiply to solve.  30x = 4500 or x = 150.

 

Now, just take 80% of 150 or 150 x 0.8 = 120.

Answer 2

Hi Mack,

 

Let given number be x.

 

30x/100=45

 

x= 45 * 100/30

 

x= 150

 

given number is 150

 

80% of 150 = 80/100 * 150=120