Question 541499
Let x = the number of Php invested at 5% per annum and 3x = the amount invested at 8% per annum. The sum of the earnings on these two amounts is given as 17,400 Php. (I don't know what these are but we can still work the problem).
First we write down the expressions for the earnings on each amount.  Change the percentages to their decimal equivalents: 5% = 0.05 and 8% = 0.08, then...
0.05x+0.08(3x) = 17,400 Simplify and solve for x.
0.05x+0.24x = 17,400 Combine the x's.
0.29x = 17,400 Divide both sides by 0.29
x = 60,000 Php and 3x = 180,000 Php.
60,000 Php was invested at 5% per annum and 180,000 Php was invested at 8% per annum.