If two typists can type two pages in two minutes, then one typist can type one page in one minute, which means she can then types a page/minute and would be able then to type 18 pages in 18 minutes since it's still a 1:1 ratio.
It doesn't say that both typists type at the same speed, in one minute, one may only be able to type a half of a page while the other can type a page and a half in the two minute time frame. Un fortunately, since there is no way to tell how fast they type individually, you must keep them together on this one.
Two typists can type two pages in two minutes... it will take two typists to type eighteen pages in eighteen minutes.







