Algebra Word Problems?
please help me with these i've been sick and i'm very behind in school
-the river boat delta duchess paddled upstream at 12 km/h, stopped for 2 h of sightseeing and paddled back at 18 km/h. how far upstream did the boat travel if the total time for the trip including the stop was 7 hours?
- lina chen invested $24,000 part at 8% and the rest at 7.2%. how much did she invest at each rate if her income from the 8% investment is two thirds of the 7.2% investment
Comments
D/12 + 2 + D/18 = 7
Multiply by 36
3D + 72 + 2D = 252
5D = 180
D = 180/5 = 36 km
Let x = amt invested at 8%
24000 – x = amt invested at 7.2 %
.08(x) = (2/3)(.072)(24000 – x)
.24x = 0.144(24000 – x)
.24x = 3456 – 0.144x
0.384x = 3456
x = 3456/0.384 = $9000 amt invested at 8%
24000 – 9000 = $15000 amt invested at 7.2 %