word problem

Question

Sam invested $1950,part of it at 6% and the rest at 8% yearly interest. The yearly income on 8% investment was $46 more than twice the income form the 6% investment.How much did he invest at each rate

Answer 1

a + b = 1950 -----> a = 1950 - b

0.08b = 2(0.06)a + 46 -----> 0.08b = 0.12a + 46

 

Substitute!

 

0.08b = 0.12(1950 - b) + 46

0.08b = 234 - 0.12b + 46

0.2b = 280

b = $1400 at 8%

 

a = 1950 - 1400

a = $550 at 6%