Question

Solve this:

B. Write T for True or F for fales.
1. A number of divisible by 8 if it is divisible by both 2 and 5.
2. A number is divisible by 25 if the difference of its alternate digits is either 0 or a multiple of 25.
3. A number is divisible by 11, if the sum of its digits is divisible by 9.

Answer 1

$$\begin{gathered} \left(1\right). \\ \mathrm{False}. \\ \mathrm{A}\mathrm{number}\mathrm{is}\mathrm{divisible}\mathrm{by}10\mathrm{if}\mathrm{it}\mathrm{is}\mathrm{divisible}\mathrm{by}2\mathrm{and}5\mathrm{both}. \\ \left(2\right). \\ \mathrm{False}. \\ \mathrm{A}\mathrm{number}\mathrm{is}\mathrm{divisible}\mathrm{by}25\mathrm{if}\mathrm{the}\mathrm{number}\mathrm{ends}\mathrm{with}00,25,50\mathrm{or}75 \\ \left(3\right). \\ \mathrm{False}. \\ \mathrm{A}\mathrm{number}\mathrm{is}\mathrm{divisible}\mathrm{by}11,\mathrm{if}\mathrm{the}\mathrm{difference}\mathrm{of}\mathrm{the}\mathrm{sum}\mathrm{of}\mathrm{the}\mathrm{digits}\mathrm{at}\mathrm{odd}\mathrm{places}\mathrm{and}\mathrm{sum}\mathrm{of}\mathrm{the}\mathrm{digits}\mathrm{at}\mathrm{even}\mathrm{places} \\ \mathrm{is}\mathrm{either}0\mathrm{or}\mathrm{a}\mathrm{number}\mathrm{divisible}\mathrm{by}11. \end{gathered}$$