One day, a person went to a horse racing area. Instead of counting the number of humans and horses, he counted 74 heads and 196 legs. How many humans and horses were there?

Let humans be x and horses be y

Both have one head each,so x+y=74 (1)

Humans have 2 legs each and horses 4 legs each…… so 2x+4y=196 (2)

In first equation x+y=74 then y=74~x (3) ……… .By solving both equations we have as under… x+3y=122 x=122-3y (4)…. Now in equation 4 we put the value of y taken from equation 3 so it will be x=122~3(74-x)…. x=122-222+3x…………. bringing x on one side x-3x=122~222 therefore -2x=~100….. x=50… put the value of x in first equation… x+y=74… 50+y=74… y=74~50…..… y=24… Now it is concluded that Humans are 50 and Horses are 24.. Now you put the values of x & y in 1st and 2nd equation … you will get x+y=74.. 50+24=74………..2x+4y=196…2×50+4×24=196.. it is proved thru equation.

just sum

10 + 10 = 20