Answer:
<em>Y alone can do the piece of work in 30 days.</em>
Step-by-step explanation:
<u>Proportions</u>
Let's make:
N = days for Y to finish the work alone
Since X alone can do it in 15 days, each day he can do a proportion of 1/15 of the piece of work.
Since Y alone can (possibly) do it in N days, each day he can do 1/N parts of the work.
Together, they do

parts of the work per day. We know they can finish it in 10 days, thus:

Rearranging:

The LCM of 10 and 15 is 30, thus operating:

Solving for N:
N = 30
Y alone can do the piece of work in 30 days.
Answer:
The answer to your question is 20 in
Step-by-step explanation:
Data
ratio 1 : 30
real length = 55 ft
toy train length = ?
Process
1.- Use ratio and proportions to solve this problem.
1 : 30 :: x : 55
solve
x = (55 x 1) / 33
Simplification
x = 55/33
result
x = 1.67 ft
2.- Convert the length to in
1 ft ------------------ 12 in
1.67 ft -------------- x
x = (1.67 x 12) / 1
-Simplification
x = 20/1
-Result
x = 20 in
Answer:
x=5
Step-by-step explanation:
Since the triangles are similar we can use ratios to solve
4.5 7.5
---- = ------
3 x
Using cross products
4.5x = 3 * 7.5
4.5x = 22.5
Divide each side by 4.5
x = 22.5/4.5
x=5
If the gym is a square with 17 meters sides, its area is given (as any other square) by the square of the side:

So, the area of the classroom is

We can deduce the side of the classroom only assuming that it is a square as well: if this is the case, the side of a square with given area is the square root of the area, so we have
