Talulah's tulips
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?
Talulah plants some tulip bulbs. When they flower, she notices something interesting about the colours. What fraction of the tulips are white?
Age
11 to 14
Challenge level
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 $60$