Eliza writes a number - the number is between 20 and 30
-it has exactly 4 factors
-one of the factors is 7
what is Eliza’s number?

the answer is 21

Step-by-step explanation:

if one of the factors is 7 and it's between 20 and 30

then it can be 21 or 28

7×3=21 and 7×4=28

now the factors of 21: 1, 3, 7, 21 (4 factors)

the factors of 28: 1, 2, 4, 7, 14, 28 (6 factors)

therfore 21 is the correct answer

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40