Word translations 4th edition strategy guide p. 93 # 8

[sanyu4]

In a diving competition, each diver has a 20% chance of a perfect dive. The first perfect dive of the competition, but not subsequent dives, will receive a perfect score. If Janet is the third diver to dive, what is her chance of receiving a perfect score?

I understand how they arrived at the answer: (8/10) (8/10) (2/10) = 12.8% but why can't we reduce these fractions further to reach the same answer. For example: 8/10 = 4/5 * 4/5 * 1/5? I don't get 12.8% when I multiply these fractions, or is it best to keep them in the original form then multiply.

Thank you

[messi10]

ummm...not sure what you mean. You still get the same answer except the calculations are a lot more complicated.

[StaceyKoprince]

Please read (and follow!) the forum guidelines before posting.

This folder is only for general strategy questions, not content or specific test problems. Check out the content / problem folders and post in the relevant folder depending upon the source of the problem you want to post (and make sure to follow the rules about banned sources). If you are a course student, you can also ask about other problems or issues before or after class.

Also, varun is right - you can simplify, and as long as you simplify correctly, you'll still get the same answer. The math you typed does also equal 12.8%.

Also note that, in this case, it is actually easier NOT to simplify, because the unsimplified multiplication works out to 128/1000, which is very easy to do. The clue there was that all three denominators were 10, so you know you're going to get a power of 10 on the denominator, and it's easy to divide by powers of 10.

With the simplified fractions, you get 16/125. Then you'd need to do long division or estimate... more annoying.