Question

Noradin Girls High Sch

Week end exercise
Q1. A bag contains 6 red counters, 5 blue counters and 4 pink counters.
A counter is selected from the bag at random.
Find the probability that the counter is:
a. Either red or pink.
b. Not pink
c. Not red.
d. Blue or red.

Answer 1

Part A

There are 6 red + 4 pink = 10 counters that are red or pink.

This is out of 6+5+4 = 15 counters total.

The probability we want is 10/15 = 2/3

Answer: 2/3

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Part B

There are 4 pink out of 15 total. That leaves 15-4 = 11 that aren't pink.

Answer: 11/15

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Part C

There are 6 red counters and 15 total. That means there are 15-6 = 9 counters that aren't red.

9/15 = 3/5

Answer: 3/5

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Part D

We have 6 red + 5 blue = 11 that are red or blue this is the exact same 11 from part B. This is because if we don't have a pink counter, then it must be red or blue (there aren't any other colors left).

Answer: 11/15