WORK AND ENERGY

first of all we have to see that the inc in momentum is only due inc in velocity(mass is constant)
let mass be m nd original vel be v
v' be the changed velocity
mv=x
mv'=11x10
so vv'=1110

% inc in KE=12mv'² -12mv²12mv² into 100

12 and m get cancelled
we are left with v'²-v²v² into 100
so the answer turns out be 11² -10²10² into 100
which is 21%

same thing.........i just unexplained the obvious portions