the sum of 3 numbers is 81 the second number is twice the first and the third number is 6times more than the second. Find the number.
Easy to translate into Math ...
let the first be x
"the second number is twice the first "
---> 2x
"the third number is 6times more than the second"
---> 2x+6
"the sum of 3 numbers is 81"
--> x + 2x + 2x+6 = 81
solve for x , and sub into my definitions
I do not understand
sum=81=a+b+c
b=2a
c=6+b
81=a+2a+6+2a
81=5a+6
a=15
b=30
c=36
15+2(15)+2(15)+6=81
15+30+30+6=81
81=81
a is15
b is 30.
c is 90.
The third number is six more than the second number.
What do you mean you don't understand
I don't understand please can you explain further
To find the numbers, we can set up three equations based on the given information.
Let's say the first number is "x".
The second number is twice the first number, so it is "2x".
The third number is 6 times more than the second number, so it can be written as "2x + 6(2x)" or simply "2x + 12x".
Now, we can set up an equation using the given information: the sum of the three numbers is 81.
x + 2x + 2x + 12x = 81
Combining like terms:
17x = 81
To solve for x, divide both sides of the equation by 17:
x = 81 / 17
x ≈ 4.765
So, the first number is approximately 4.765.
The second number is twice the first number:
2x ≈ 2 * 4.765
2x ≈ 9.53
So, the second number is approximately 9.53.
The third number is 6 times more than the second number:
2x + 12x ≈ 9.53 + (6 * 9.53)
2x + 12x ≈ 9.53 + 57.18
2x + 12x ≈ 66.71
So, the third number is approximately 66.71.
To summarize, the three numbers are approximately:
First number: 4.765
Second number: 9.53
Third number: 66.71