kangaroo math Exam Numerical Ability Ratio and Proportion

The tango is danced in pairs, each consisting of one man and one woman. At a dance
evening no more than 50 people are present. At one moment 3/4 of the men are dancing with
4/5 of the women. How many people are dancing at that moment?
(A) 20 (B) 24 (C) 30 (D) 32 (E) 46

Read Solution (Total 1)

(B) 24

Let total number of men=x and women=y, then
Dancing men=(3/4)x and women=(4/5)y
As dancing men= Dancing women => (3/4)x =(4/5)y or 15x=16y
This condition satisfies for x=16 & y=15 where it is given, x+y is less than equal to 50.
So total people dancing=(3/4)x + (4/5)y =(3/4)*16 + (4/5)*15= 24
7 years agoHelpfull: Yes(2) No(1)

kangaroo math Other Question

An equilateral triangle starts in a given position and is moved to new positions in a
sequence of steps. At each step it is rotated about its centre, first by 3◦
, then by a further 9◦
,
then by a further 27◦
, and so on (at the n-th step it is rotated by a further (3n
)
◦
). How many
different positions, including the initial position, will the triangle occupy? Two positions are
considered equal if the triangle covers the same part of the plane.