Maths Olympiad Prep

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, 2023

Combinatorics Difficulty 1.1 Junior Find the answer Canada

Lucy tracked the number of cardinals and the number of blue jays
that she saw each day for three days. The graph below summarizes the
birds that she saw.

Figure 0

How many more cardinals than blue jays did she see over the three
days?

Pick one

Solution

On Day 1, Lucy sees 2 blue jays and 3 cardinals, and so sees 1
more cardinal than blue jay.

On Day 2, Lucy sees 3 blue jays and 3 cardinals.

On Day 3, Lucy sees 2 blue jays and 4 cardinals, and so sees 2 more
cardinals than blue jays.

Thus, over the three days, Lucy saw 1+0+2=31 + 0 + 2 = 3 more cardinals than blue jays.

Figure for this problem

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