Z score = (x -mean) / standard deviation.
For this problem X = 50 cm.
Z-score = (50 - 49.2) / 1.8
Z score = 0.8 / 1.8
Z score = 0.44
Look up 0.44 on a z-score table.
0.44 = 0.6700
0.67 x 100 = 67% will be 50 cm or longer.
Divide 18 by 3 and double it to get 12 :))))))
take father's age as x
if it is doubled i.e 2x .we get the answer as 20 less than 100 which means 100-20=80
accordingly the equation will be 2x=80
x=40
given that ,
son is 1/4 th of his father
hence ,
son = 1/4×(x)
I.e, 1/4×40 =10
Hope it helps
The rational root are x= 7,-3,-6
You can find them by substituting y for 0