Asked by Omar

Find all pairs of numbers such that when they are added they equal 100, and when
they are multiplied they are at least 2000.

Answers

Answered by Steve
maximum product occurs when a=b=50
That makes the product 2500
The larger a gets, the smaller b must get, so try
a=40 b=60: ab=2400
a=30 b=70: ab=2100
a=20 b=80: ab=1600
and narrow in on it.

Or, algebraically,

a(100-a) >= 2000
a^2 - 100a + 2000 <= 0
10(5-√5) <= a <= 10(5+√5)
27.6 <= a <= 72.3

so, 28 < a <= 72

check:
28*72 = 2016
27*73 = 1971
There are no AI answers yet. The ability to request AI answers is coming soon!

Related Questions