15. The universal set (ε) contains the numbers 31, 32, 33, 34, 35, 36, 37, 38, 39 and 40.
A is the set of odd numbers. B is the set of multiples of 3.
(a) Show this information on the Venn diagram below. [2]
(b)
A number is selected at random from the universal set (ε).
Find the probability that the number selected is an odd number but not a multiple of 3. [2]
Mark scheme (a)
Scheme
Marks
Comments
A correct Venn diagram
B2
B1 for 7, 8 or 9 unique numbers correctly placed. OR B1 for everything correct except sets A and B reversed OR B1 for all correct with 32, 34, 38 and 40 missing
Mark scheme (b)
Scheme
Marks
Comments
3/10 or 0.3 oe
B2
ISW FT either the Venn diagram in (a) or the list BUT not both for B2 or B1 to candidates’ advantage
B1 for a numerator of 3 or a denominator of 10 in a fraction < 1. Allow B1 for ‘3 out of 10’ or ‘3 in 10’.
We'd like to use Google Analytics cookies to count visits and see which pages help most. They're optional, and the site works exactly the same either way. Privacy policy
