investment word problem

Question

Mrs. P invested $100,000 in 2 different companies, one earning 6% and the other earning 12% proffit.  IF mrs. P made 2 times as much proffit from the 12%, how much did she invest in the company that made 6%?

Answer 1

Let's assume $x was invested in the company that earns 6% profit,

hence she invested $(100,000-x)  in the company that earns 12% profit

Given that, 2*(6%of x)=12% of (100,000-x)

=>2*(6x/100) = (12/100)*(100,000-x)  ............ By adjusting operators

=>[12*x]/100 = [12*(100,000-x)]/100 ............ By adjusting operators

=>       12*x   =12*(100,000-x) ...... By multiplying both sides by 100

=>              x = 100,000-x ...... By dividing both sides by 12

=>             2x = 100,000 ...... By adding x to both sides

=>               x=50,000 ...... By dividing both sides by 2