A girl's age in 12 years' time is the square
of her present age. Find her present age.

her present age is 4

Step-by-step explanation:

Proof: 4+12=16

Square root 4 is 16

  4

Step-by-step explanation:

Let x represent her present age. The given relation is ...

  x +12 = x^2

Putting this in standard form, we can factor it:

  x^2 -x -12 = 0

  (x -4)(x +3) = 0

Solutions to this quadratic are x = 4, x = -3. The -3 solution is extraneous in this context.

The girl's present age is 4.

50 min

step-by-step explanation:

they will be decreasing both their times in half

60 / 2 = 30

40/2 = 20

30 + 20 = 50

25% is the answer