3 yellow tulips
Given that ,
There are 15 red tulips every 9 yellow tulips and we are to find the number of yellow tulips every 5 red tulips ,
therefore,we would find out the ratio between the red and the yellow one and then use cross multiplication method,
for this ,let the number of yellow tulips every 5 red one be x,
therefore,
15/9 = 5/x
15x = 9*5
15x = 45
x = 45/15
x = 3
Henceforth, the number of yellow tulips for every 5 red ones is 3 .