angus invested $18,000 part at 3% and part at 5%.?

Imogene Neiswander: Sum invested=x - Sum invested=18000-xR=5% - R=3%T=1 yr. - T=1 yr. SI1=PRT/100 - SI2=PRT/100 =(x*5*1)/100 - =(18000-x)*3*1/100 =5x/100 - =3(18000-x)/100 Total SI=SI1+SI2600=(5x+54000-3x)/100600*100=2x+5400060000=2x+5400060000-54000=2x6000=2x 3000=xSum invested at 5%=x=$3000Sum invested at 3%=18000-x=18000-3000=$15,000...Show more

Hubert Jestes: Let us assume he had invested x $ at 3%.Then he would have invested (18000-x) $ at 5%Total interest rate = $600Therefore 3*x/100+5*(18000-x)/100 = 600which on solving should give x = 15000 and 18000-x = 3000Therefore he invested $15000 at 3% and $3000 at 5%...Show more

Bibi Tyron: If x is investd at 3% and y at 5%, we have x + y = 18,000 and 3x + 5y = 600! 00 or 3x = 60000 - 5y and substituting in the other equation, we have 60000 - 5y + 3 y = 54000 (we multiplied the first equation by 3)or - 2y = 54000 - 60000 = - 6000 or y = 3000 So, x = 18000 - y = 15000 Let us check. 15000 at 3% gives 450 dollars and 3000 at 5% gives 150 dollars totalling 600 dollars as interest. So, our calculation is OK....Show more