so what is exactly the question
If she reads 50 pages of a book in 50 minutes, just divide 50 by 50.
50 / 50 = 1 She reads one page of a book a minute.
Lets say the race is x km long.
That means she ran 65% of x.
And that also means that 65% of x = 3
So 65%*x=3
65/100x=3
x=3*100/65
x=300/65
x=4.62
3.2d - 4d = 2.3d + 3...simplify by combining like terms
-0.8d = 2.3d + 3....subtract 2.3d from both sides
-0.8d - 2.3d = 3 ...simplify again
-3.1d = 3...divide both sides by -3.1
d = 3/ -3.1
d = - 0.97
or
3.2d - 4d = 2.3d + 3....multiply the equation by 10, gets rid of the decimals
32d - 40d = 23d + 30....subtract 23d from both sides
32d - 40d - 23d = 30....simplify
-31d = 30...divide by -31
d = -30/31
d = - 0.97