Question:

Given \(5\) different green toys, \(4\) different blue toys, and \(3\) different red toys, how many combinations of toys can be chosen taking at least one green and one blue toy?

Show Hint

If at least one object must be selected from \(n\) distinct objects, the number of selections is \[ 2^n-1 \] because the empty set is excluded.
Updated On: Jun 24, 2026
  • \(32\times 16\times 4\)
  • \(31\times 15\times 4\)
  • \(32\times 16\times 8\)
  • \(31\times 15\times 8\)
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is D

Solution and Explanation

Step 1: Select green toys.
There are \(5\) different green toys.
The number of ways to choose any subset of these toys is \[ 2^5=32 \] But at least one green toy must be selected, so exclude the empty selection: \[ 32-1=31 \] Thus, the number of ways to choose green toys is \[ 31 \]

Step 2: Select blue toys.
There are \(4\) different blue toys.
Total subsets: \[ 2^4=16 \] Since at least one blue toy must be selected, exclude the empty set: \[ 16-1=15 \] Thus, the number of ways to choose blue toys is \[ 15 \]

Step 3: Select red toys.
There are \(3\) different red toys.
Red toys may or may not be selected.
Hence, total possible selections are \[ 2^3=8 \]

Step 4: Apply multiplication principle.
Total number of combinations: \[ 31\times 15\times 8 \]

Step 5: Final conclusion.
Therefore, \[ \boxed{31\times 15\times 8} \]
Was this answer helpful?
0
0