70
30
1000 / -50 is equal to -20.
10 out of 20 is equal to half, or 50%
In fact, score does not equal 50 - score equals 20. "Four score and seven years ago" is equal to 4 x 20 + 7 = 87 years.
-20
1000
8:20 + 1:50 = 10:10
40% of 50% of 100 is equal to 20.
There are infinitely many quadratics that can equal 20.For example, given any positive number, a, a*x^2 + 20 will equal 20 for x= 0.
70
If you have two pairs of numbers whose sum is the same, their product increases as the two numbers get nearer to half the sum. The product is a maximum at that value. 70 * 30 = (50+20)*(50-20) The right hand side is the factorisation of the difference of two squares, and can be shown to be equal to 502 - 202 Since 202 must be positive (it is a square), 70*30 must be less. For all values of x, (50+x)*(50-x) is less than or equal to 50*50=2500 with equality attained only when x = 0.
Negative 20.