Answer :
To solve the problem where the sum of two numbers is 40 and the second number is 5 less than twice the first number, we will use a guess and check method with the numbers provided.
We are given four possible values for the first number, [tex]\( x \)[/tex]: 15, 20, 25, and 30. Let's evaluate each one to see which one fits the conditions.
1. First Number [tex]\( x = 15 \)[/tex]:
- Calculate the second number using the formula:
[tex]\( y = 2x - 5 \)[/tex]
[tex]\( y = 2(15) - 5 = 30 - 5 = 25 \)[/tex]
- Check the sum:
[tex]\( x + y = 15 + 25 = 40 \)[/tex]
This option satisfies both conditions: the sum is 40, and the second number is 5 less than twice the first number.
Since this calculation satisfies all the conditions of the problem, the first number [tex]\( x \)[/tex] is 15. Therefore, the value of the first number is [tex]\( \boxed{15} \)[/tex].
We are given four possible values for the first number, [tex]\( x \)[/tex]: 15, 20, 25, and 30. Let's evaluate each one to see which one fits the conditions.
1. First Number [tex]\( x = 15 \)[/tex]:
- Calculate the second number using the formula:
[tex]\( y = 2x - 5 \)[/tex]
[tex]\( y = 2(15) - 5 = 30 - 5 = 25 \)[/tex]
- Check the sum:
[tex]\( x + y = 15 + 25 = 40 \)[/tex]
This option satisfies both conditions: the sum is 40, and the second number is 5 less than twice the first number.
Since this calculation satisfies all the conditions of the problem, the first number [tex]\( x \)[/tex] is 15. Therefore, the value of the first number is [tex]\( \boxed{15} \)[/tex].