Modi Vs. Rahul

A + B = 90 and 10A + 15B = 1200 solving, A = 30, B = 60

10A = 300 and 15B = 900 won by 900 – 300 = 600

well, lets begin by assigning variables to number of vehicles for A and B.

• $\left\lceil x \right\rceil$ - number of vehicles for A
• $\left\lceil y \right\rceil$ - number of vehicles for B

we then have $10x + 15y = 1200$ also, $\left\lceil x \right\rceil +\left\lceil y \right\rceil \ge 90$ we use ceiling function for x and y as there is a possibility that $y$ takes decimal values and number of vehicles can't be decimals.

so for maximum votes in favour of B, we need to have maximum value for variable $y$

trying out $x=3$ we get $y=78$ but $x+y=81$ which is $<90$

trying out $x=6$ we get $y=76$ but $x+y=82$ which is $<90$

from trying the two sets above, we note that for every increase in $x$ by $3$ there is overall increase in number of vehicles by $1$

hence, for when $x=30$ we get $y=60$ and we satisfy $x+y \ge 90$

Thus, number of supporters of $A=300$ and $B=900$ giving us the difference $\boxed{600}$

Hey yo.

for total number of vehicles,

A + B = 90

A = 90 - B (1st)

for total number of voters,

10A + 15B = 1200 (2nd)

substitute (1st) into (2nd),

10(90 -B) + 15B = 1200

5B = 300

B = 60

A = 90 - 60 = 30

A has 30 vehicles while B has 60 vehicles,

A has (30 x 10) = 300 votes,

B has (60 x 15) = 900 votes,

The votes difference as B won the election = 900 - 300 = 600,

Thanks....