Divide through everything by <em>b</em> :

Since <em>a/b</em> < <em>c/d</em>, it follows that

Multiply through everything on the right side by <em>b/d</em> to get

and so (<em>a</em> + <em>c</em>)/(<em>b</em> + <em>d</em>) < <em>c/d</em>.
For the other side, you can do something similar and divide through everything by <em>d</em> :

and <em>a/b</em> < <em>c/d</em> tells us that

Then

and so (<em>a</em> + <em>c</em>)/(<em>b</em> + <em>d</em>) > <em>a/b</em>.
Then together we get the desired inequality.
Answer:
x = 8
Step-by-step explanation:
If the number 212x5 is a multiple of 3, the sum of the digits needs to be a multiple of 3, so we have:
2 + 1 + 2 + x + 5 = 10 + x
The value of x can be 2, 5 or 8
If the number is a multiple of 11, we have to calculate the first number minus the second, plus the third, minus the fourth... and so on, and the result needs to be a multiple of 11. So we have:
2 - 1 + 2 - x + 5 = 8 - x
x needs to be 8, so we have 8 - 8 = 0, that is a multiple of 11.
So the value of x is 8.
Answer:
10
10
Step-by-step explanation:
One fifth of fifty is 10.
Answer:
5 and 1/8
Step-by-step explanation:
Answer:
41.
Step-by-step explanation:
The range = highest - lowest value
= 65 - 24
= 41.