Tuesday, January 17, 2012

Simple Ratio problem that often confuses

Sum of three nos is 98. The ratio between 1 and 2 is 2:3. The ratio between 2 and 3 is 5:8 .
Find the second no?


Answer is simple:

Let x,y,z be numbers.
x/y=2/3 , So, 3x=2y. And y/z=5/8 , So 8y=5z
Sum is 98, So 2y/3+y+8y/5=98. Therefore y=30
Numbers are 20,30,48

Simple maths puzzzle

If The product of two positive numbers is p. If each of the numbers is increased by 2, the new
product is how much greater than twice the sum of the two original numbers?
(A) p-2
(B) p
(C) p+2
(D) p+4
(E) 2p+4




Answer: (before looking solution, try solving it)

Let numbers be x,y. So xy=p
(x+2)(y+2)-2(x+y)=xy+4
So p+4 is answer