Hello! Your answer is B, 10 minutes.
Say the x = minutes taken to do the job. You can set up an equation like this to solve this.

This is representative of the situation. The fractions each represent <u>how much each person does in a minute</u>, and when they're multiplied by x, that's <u>how much of the project they get done</u> based off of the minutes they work together on the job. Add the two together, and you get <u>how much of the project is finished in x amount of time</u>. Set it equal to 1, as you are looking for 100% completion.
Once you have this equation, find a common denominator, add, and solve.





Therefore, it will take them 10 minutes to do the job together.
Hope this helps!
66 is the 100%
we can solve this problem by the rule of three.
Therefore:
66------------------------100%
x--------------------------150%
x=(66 * 150%) / 100%=99
Answer 150% of 66 is 99.
Other method:
150% of 66=1.5 *66=99
Answer: 150% of 66 is 99.
<span>, y+2 = (x^2/2) - 2sin(y)
so we are taking the derivative y in respect to x so we have
dy/dx use chain rule on y
so y' = 2x/2 - 2cos(y)*y'
</span><span>Now rearrange it to solve for y'
y' = 2x/2 - 2cos(y)*y'
0 = x - 2cos(y)y' - y'
- x = 2cos(y)y' - y'
-x = y'(2cos(y) - 1)
-x/(2cos(y) - 1) = y'
</span><span>we know when f(2) = 0 so thus y = 0
so when
f'(2) = -2/(2cos(0)-1)
</span><span>2/2 = 1
</span><span>f'(2) = -2/(2cos(0)-1)
cos(0) = 1
thus
f'(2) = -2/(2(1)-1)
= -2/-1
= 2
f'(2) = 2
</span>