We take interest+interest+interest to equal interest 0.041=4.1%(25000) the amount invested+0.056=interest they want=0.048 the total amount wanting to earn 4.8% and x is the added money to invest. 0.041(25000)+0.056x=0.048(25000+x) 1025+0.056x=1200+0.048x subtract the 0.048 from both sides 1025+0.008x=1200+x Subtract the 1025 from both sides 1025-1025+0.008=1200-1025+x 0.008x=175+x Now divide 175 by 0.008 x=21,875
