Talulah's Tulips
Age
11 to 14
Challenge level
Weekly Problem 10 - 2017
Talulah plants some tulip bulbs. When they flower, she notices something interesting about the colours. What fraction of the tulips are white?
Problem
Talulah plants $60$ tulip bulbs. When they flower, she notes the following:
- Half the tulips are yellow
- One third of those which are not yellow are red
- One quarter of those which are neither red nor yellow are pink
- The remainder are white
If you liked this problem, here is an NRICH task that challenges you to use similar mathematical ideas.
Student Solutions
Answer: $\frac14$
Using fractions directly
Image
$\frac12$ $\frac13\times\frac12=\frac16$ $\frac 12\times 16 = \frac1 {12}$
so $\frac3{12}=\frac14$ are white
Using numbers
Image
$\frac12$ of $60=30$ $\frac13$ of $30=10$
$20$ left $\frac14$ of $20=5$
$15$ are white
which is $\frac14$ of $60$