Answer:
41
Step-by-step explanation:
Given Expression:
(4 x 9 - 21) \ 3+6^2
Multiply 4 and 9 to get 36.
36 - 21 / 3 + 6^2
Subtract 21 from 36 to get 15.
15/3 + 6^2
Divide 15 by 3 to get 5.
5+6^2
Calculate 6 to the power of 2 and get 36.
5+36
Add 5 and 36 to get 41.
41
Answer:
9 mph
Step-by-step explanation:
-let x be the speed of current and t be time. The speed equation for both directions can then be represented as:

#Since t is equal in both, we can do away with t.
#We the divide the downstream equation by the upstream equation as:

Hence, the boat's speed in still water is 9 mph
90 words in 4 minutes is the same as 45 words in 2 minutes because you divide both sides by 2. 2 goes into 10, 5 times, so 45x5=225.
You can expect her to type 225 words in 10 minutes.