Old rate = 10 words/min = 600 words/hour
New rate = twicw the Old rate + 10
New rate = (2 * 600) + 10 = 1210

Explanation

To find the new rate in words per hour, start by setting up an equation to find this value:

New words per hour = 10 + 2(Old words per hour)

The old rate was given in words per minute, so convert to words per hour:

10 words per min × 60 min per hour = 600 words per hour

Now plug into the equation:
New words per hour = 10 + 2(600) = 1,210

Note that it would be dangerous to start by working with the rate per minute. If you did so, you might calculate 10 + 2(10) = 30 words per minute, then 30 × 60 = 1,800 words per hour. This rate is inflated because you added an additional 10 words per minute instead of per hour. Perform the conversions right away!

when we say this- "The old rate was given in words per minute, so convert to words per hour:

10 words per min × 60 min per hour = 600 words per hour"


do you mean:-
10words/1min now converting that 1 min to hours (10words)/((1/60)hours) which equals 600 words per hour

Yes . please sir refer to our quant book word problems chapter https://gre.myprepclub.com/forum/gre-quant ... tml#p52437

You lack of key fundamentals