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AP EAMCET · Maths · Binomial Theorem

The greatest integer \(\mathrm{r}\) such that \(30^{\mathrm{r}}\) divides 30 ! is

  1. A \(8\)
  2. B \(7\)
  3. C \(6\)
  4. D \(5\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(7\)

Step-by-step Solution

Detailed explanation

Since \(30^{\mathrm{r}}\) divides \(30 !\) Now \(30^{\mathrm{r}}=2^{\mathrm{r}} \times 3^{\mathrm{r}} \times 5^{\mathrm{r}}\) Since 5 divides 30 ! So \(r=\left[\frac{30}{5}\right]+\left[\frac{30}{5^2}\right]=6+1=7\)