Question 1167457
Probability of getting exactly three questions right:
{{{(0.25)^3 * (0.75)^7 * (10!/(3!*7!))}}} = 0.2503
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Probability of getting exactly two questions right:
{{{(0.25)^2 * (0.75)^8 * (10!/(2!*8!))}}} = 0.2816
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Probability of getting exactly one question right:
{{{(0.25)^1 * (0.75)^9 * (10!/(1!*9!))}}} = 0.1877
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Probability of getting exactly zero questions right:
{{{(0.75)^10}}} = 0.0563
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Probability of getting "at most three" questions right:
0.2503 + 0.2816 + 0.1877 + 0.0563 = <b>0.7759</b>