- Home
- Standard 11
- Mathematics
4-2.Quadratic Equations and Inequations
hard
The number of non-negative integer solutions of the equations $6 x+4 y+z=200$ and $x+y+z=100$ is
A
$3$
B
$5$
C
$7$
D
Infinite
(KVPY-2019)
Solution
(c)
Given equations
$6 x+4 y+z=200$ and $x+y+z=100$
By Eqs.$(i)$ and $(ii)$, we get
$5 x+3 y=100$
For non-negative integer solutions, when
$x=2$, then $y=30$
$x=5$, then $y=25$
$x=8$, then $y=20$
$x=11$, then $y=15$
$x=14$, then $y=10$
$x=17$, then $y=5$
and $x=20$, then $y=0$
In every case $z=100-(x+y) > 0$
So, total number of non-negative integral solutions are $7.$
Standard 11
Mathematics