The mean age of Mr Jasmi, Miss Haslinda and their three children is 38 years. The mean age of their three children is 18 years. Calculate the mean age of Mr Jasmi and Miss has Linda

68

Explanation:

Let x be the age of Mr Jasmi
y be the age of Miss Haslinda
a + b + c be the age of the 3 children

We can write:
(x + y + a + b + c)/5 = 38

But:
(a + b + c)/3 = 18
a + b + c = 18(3)
a + b + c = 54

Substitute this value to our first equation

(x + y + 54)/5 = 38
x + y + 54 = 38(5)
x + y + 54 = 190
x + y = 190 - 54
x + y = 136

Thus:
Mean age of (mr jasmi and miss Linda) = (x+y)/2

But x + y = 136

=> mean age = 136/2 = 68

Best answer that i found on yahoo ok   set :   x= length of 2nd piece in cm  x- 3= length of 1st piece in cm  x-4= length of 3rd piece in cm  then since you know they all came from the 20 cm ribbon you add them together and set them equal to 20x+ x-3 +x-4 = 20  3x - 7= 20  3x= 27  x= 9  the shortest piece is the third piece which is x- 4  x-4  9-4 = 5  the length of the smallest piece is 5 cm.  the other lengths are  9 cm  6 cm