1. The sum of three numbers is 301. The second number is 3 less than twelve times the first number. The third number is 4 more than seven times the first number. Find the three numbers.
I need to know how you get the answers also.
2007-10-19 11:01:31 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Let first number = a, second number = b, and third number = c
So a+b+c = 301
b = 12a-3 (second number is 3 LESS than TWELVE TIMES the first number).
c = 4+7a (third number is 4 MORE than SEVEN TIMES the first number)
Now substitute b with 12a-3, and c with 4+7a
So,
a + (12a-3) + (4+7a) = 301
a + 12a - 3 + 4 + 7a = 301
a + 12a+7a-3+4=301
20a+1= 301
20a = 301-1
20a = 300
a = 300/20
a = 15
Find b,
b=12a-3
b= 12(15)-3 = 177
Find c,
c=4+7a
c=4+7(15)
c=4+105
c=109
Check the answers,
a+b+c = 301
15+177+109= 301
12a-3=b
12(15)-3=180-3= 177
c=4+7a
c=4+7(15) = 4+105 = 109
2007-10-19 11:23:18 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Let the first number be x, then
1st number = x
2nd number = 12x - 3
3rd number = 7x + 4
x + 12x - 3 + 7x + 4 = 301
20x = 300
x = 15
The numbers are
1st number = 15
2nd number = 12x - 3 = 12(15) - 3 = 177
3rd number = 7x + 4 = 7(15) + 4 = 109
check 15 + 177 + 109 = ???
2007-10-19 18:07:31 · answer #2 · answered by Terry S 3 · 0⤊ 0⤋
x+y+z = 301
y = 12x -3
z = 7x + 4
x + 2x + 12 x - 3 + 7x + 4 = 301
20 +1 = 301
20x = 300
x = 15
y = 177
z = 109
2007-10-19 18:08:42 · answer #3 · answered by norman 7 · 0⤊ 0⤋
1st number = 150
2nd number= 1797
3rd number= 1054
2007-10-19 18:41:48 · answer #4 · answered by blah blah 2 · 0⤊ 0⤋
OK so write it in an algerbraic expression.
x + n + y = 301
x = x
n = 12x - 3
y = 7x + 4
Now try solving for x.
I hope this helped.
2007-10-19 18:15:20 · answer #5 · answered by sixthstring 2 · 0⤊ 0⤋