If he bikes for 10 miles per hour and 8 miles per hour for the same distance x miles, he went 10 miles per hour for x/10 hours, as Distance = Rate*Time and on the way back he would go for x/8 hours. So then he went 2x distance, in x/8 + x/10 hours. Since x/8 + x/10 = 10x/80 + 8x/80 = 18x/80 = 9x/40, he went 2x miles in 9x/40 hours. this can be converted into a rate with the above equation Distance = Rate*Time, so 2x=(9x/40) * Rate, thus we divide by 9x/40 on both sides to get 80x/9x = Rate, the x cancels out, and we get 80/9 Miles per hour.
Answer:
78, 1275
Step-by-step explanation:
a) 12th= 78
b) 50th=1275
Answer:
350 tickets
Step-by-step explanation:
if you do 42/350, it would equal 12%, so 350 is the total
One of the main reasons you have to show work for math is because your teacher needs to know that you understand the concept. Also, showing work helps your teacher know that you didn't cheat using an online calculator that just gives you an answer.
Answer:
38π cubic units
Step-by-step explanation:
The volume V = ∫₀²πy²dx
Since y = 3x + 1, dy = 3dx ⇒ dx = dy/3
So, when x = 0, y = 3(0) + 1 = 0 + 1 = 1
when x = 2, y = 3(2) + 1 = 6 + 1 = 7
So, changing the variable to y and the limits of integration from y = 1 to y = 7, we have
V = ∫₀²πy²dx
V = π∫₁⁷y²dy/3
V = π[y³/3]₁⁷/3
V = π[y³]₁⁷/9
V = [7³ - 1³]π/9
V = [343 - 1]π/9
V = 342π/9
V = 38π cubic units
