Answer:
8 positive integers.
Step-by-step explanation:
One value of n would be 15 because 225 = 15^2.
Other values are 225 * n where 15n <= 1000 and n is a perfect square.
So n = 4 gives us 225* 4 = 900 which is a perfect square and 15*4 = 60.
n = 9 gives us 225 * 9 which is a perfect square and 15*9 = 135.
n = 16 gives us 225*16 and 15*16 = 240 , so OK.
n = 25 gives a perfect square and and 15*25 = 375 - so OK.
n = 36 gives a perfect square and 15*36 = 540 - so OK.
n = 49 gives a perfect square and 15*49 = 735 - so OK.
n = 64 gives a perfect square and 15*64 = 960 - so ok.
n = 81 gives a perfect square and 15 * 81 = 1215 so NOT ok.
Answer:
3sqrt(2) ................
Answer: 20 mph
Explanation:
Speed is a physical quantity which is equal to the ratio between the distance covered (d) and the time taken (t):

In the first part of the problem, the plane flew a distance of d=400 mi in a time of t=2.5 h. The speed of the plane in this case was the difference between the proper speed of the plane, v, and the speed of the wind, w, since the plane flew opposite to the wind. So we can write:
(1)
During the return trip, the plane flew with a speed (v+w), since the wind was on the tail, and it took 2 hours to cover the same distance:
(2)
So we have two equations with two unknown variables. From (1), we get

Substituting into eq.(2)

So, the speed of the wind was 20 mph.
The answer is 4 because the square root of 4 is -2, and that multiplied by 2 is -4