Question

x,y,z are consecutive positive integers, such that x < y < z. If the units' digit of x2 is 4 and the units' digit of y2 is 1, what is the units' digit of z2?

Answer 1

since unit digit of x^2 is 4 then x can be 2 or 8
and unit digit of y^2 is 1 then y can be 1 or 9
since x<y and both of them r consecutive therefore x and y are 8 and 9
now as xyz are consecutive therefore z is 10 and unit digit of z^2 is 0

hope this helps:p

Answer 2

x<y<z 

∴ x2<y2<z2

Such conditions are fulfilled when,

x = 8, y = 9 and z = 10

∴x2 = (10)² = 100
So, unit digit of z is 0