# Thread: Arithmetic challenge involving percents

1. ## Arithmetic challenge involving percents

.

Can you work all of these out in your head and/or on paper in less than a total of two minutes?

65% of 10

18% of $\displaystyle \ 16\tfrac23$

35% of 20

8% of 25

12% of $\displaystyle \ 33\tfrac13$

38% of 50

9% of $\displaystyle \ 66\tfrac23$

44% of 75

2. ## Re: Arithmetic challenge involving percents

Originally Posted by greg1313
.

Can you work all of these out in your head and/or on paper in less than a total of two minutes?
No.

I am answering the real question here.

3. ## Re: Arithmetic challenge involving percents

Yes. Some mental shortcuts help; for example 18% of 16$\frac 2 3$ is the same as 16$\frac 2 3$% of 18, which is 1/6 of 18.