This is a hard question because usually boys prefer apple juice
We can use Triangle Inequality Theorem, the length of the third side of a triangle must always be between (but not equal to) the sum and the difference of the other two sides.
4.1 - 1.3 < x < 4.1 + 1.3
2.8 < x < 5.7
so, the answer is 2.8 < x < 5.7
7 = r^1/2 is the same as saying 7 = square root of r. So, to get rid of the square root sign on the r, you need to square it, and when you do something to one side of the equation, you have to do the same to the other side. So after squaring both sides, you get 49 = r.
7/5 = 14/10 = 28/20
Numerator = x
Denominator = x-4
Add 3 to both:
x +3 / (x-4+3)
x+3 = 14
(x-4 +3) = 10 = x-1 = 10
x = 11
Check:
11 -4 = 7 ( denominator is 4 less than the numerator.)
add 3 to both:
11+3 = 14
7+3 = 10
14/10 reduces to 7/5
The original fraction would be 11/7