The day before a show, a theatre had sold adult and child tickets in the ratio 9:4.
On the day of the show, the theatre sold 20 more adult tickets and no more
child tickets.
The ratio of adult to child tickets sold became 8:3.
Work out how many adult tickets had been sold the day before the show.

the correct answer is 5 6 and 7

step-by-step explanation:

given that there are two triangles j'k'l' and jkl>

the former is got by dilating the second one.

when drawn on a grid, (graph paper) coordinates of vertices of first triangle is

(6,12)j, (9,6)k and (12,9)l

side jk has length = distance between j and k

=

side j'k'=distance between j' and k'

=

ie j'k'l' has sides 1/3 of that of corresponding sides of jkl.

hence scale factor of 1/3 is used to get j'k'l'from jkl