eleven less than twice a number is at most 25 and at least 15
Replace the word "eleven" by "11".
11 less than twice a number is at most 25 and at least 15
Replace the words "a number" by "x".
11 less than twice x is at most 25 and at least 15
Replace "twice x" by 2x
11 less than 2x is at most 25 and at least 15
Replace the words "11 less than 2x" by "2x-11" (You make 2x less by subtracting from it)
2x-ll is at most 25 and at least 15
Replace the words "is at most" by "≦" which means "(is) less than or equal to"
2x-ll ≦ 25 and at least 15
Replace the words "(is) at least" by "≧" which means "(is) greater than or equal to"
2x-ll ≦ 25 and ≧ 15
That means that 2x-ll ≦ 25 and 2x-ll ≧ 15
Change the inequality on the right by reversing sides and reversing
the inequality:
That means that 2x-ll ≦ 25 and 15 ≦ 2x-11
Write the second one first and the first one second:
15 ≦ 2x-11 and 2x-ll ≦ 25
No need for the duplication of 2x-11, so write:
15 ≦ 2x-ll ≦ 25
That's the inequality.
To solve it, add 11 to all three sides:
15+11 ≦ 2x-ll+11 ≦ 25+11
26 ≦ 2x ≦ 36
Divide all three sides by 2
13 ≦ x ≦ 18
In interval notation that's
[13, 18]
Edwin