As you are looking for 1.75 minutes (or 105 seconds), the best thing to do is to find how many words she can type in 0.25 minutes (this is a quarter, and you can divide 1.75 by this). To find a quarter, you have to divide by 4, 120/4= 30. Therefore, every 15 seconds, Dorothy can type 30 words. As you've got 105 seconds, divide this by 15, and this gives you 7. Then multiply 30 by 7, and this gives you 210. Dorothy can type 210 words in 1.75 minutes Hope this helps :)
Each team needs two people for a 3-legged race. Therefore, the number of orders (combinations) of 2 people at a time from 8 is ₈C₂ = 8!/(2!6!) = (8*7*6!)/(2*6!) = (8*7)/2 = 56/2 = 28
