Answer:
11.4 years
Step-by-step explanation:
We assume you want to know the time it takes for Lucy's investment of $1200 to have a value of $6400. The compound interest formula is good for finding that.
FV = P(1 +r/n)^(nt)
for principal P invested at rate r per year for t years, compounded n times per year. We want to find t such that ...
6400 = 1200(1 +0.15/4)^(4t)
16/3 = 1.0375^(4t) . . . . divide by 1200
log(16/3) = 4t·log(1.0375) . . . . take logarithms
t = log(16/3)/(4·log(1.0375)) ≈ 11.4
It will take about 11.4 years for Lucy's investment value to be $6400.
Answer:
Step-by-step explanation:
Both cars, X and Y travelled 80 miles each.
Speed = distance/time
If car X took 2 hours to travel 80 miles, it means that the speed at which car X travelled is
80/2 = 40 mph
If car Y traveled at an average speed that was 50 percent faster than the average speed of car X, it means that the speed at which car X travelled is
40 + 0.5 × 40 = 60 mph
Time = distance/speed
Therefore, time taken by car Y to travel 80 miles is
80/60 = 1.33 hours
Answer:
e= 10h+5
Step-by-step explanation:
h is no of hours
e is earnings
For starters, create an equation to show David's earnings. We can do this using Danielle's as a basis, which is set up as y=(# of hours)x+(bonus). This gives us y=12x+80. Now, as we need both their ys to be equal, we just set both equations equal to each other, making 15x+50=12x+80. Now, we solve for x, starting with 15x+50=12x+80, subtracting 12x from both sides to get 3x+50=80, subtracting 50 from both sides to get 3x=30, and dividing three from both sides to get x=10. To check, we just plug in our answer to both equations and see if the ys match up. With Danielle's equation, we get y=15(10)+50=150+50=200 and with David's equation, we get y=12(10)+80=120+80=200, proving that our answer is correct.
Answer:
subtract 1 then divide 2
Step-by-step explanation:
