a2zinterviews

1.	If log 2 = 0.30103, the number of digits in 520 is
	A.  14
	B.  16
	C.  18
	D.  25

Solution

Log 520 =20 log 5 =20 ×[log(10/2)] =20 (log 10 - log 2) =20 (1 - 0.3010) =20×0.6990 =13.9800. Characteristics = 13. Hence, the number of digits in Log 520 is 14.

2.	The value of log2 16 is
	A.  1/8
	B.  4
	C.  8
	D.  16

Solution

Let log216 = n. Then, 2n = 16 = 24 ‹=› n=4.

3.	If log 32 x= 0.8, then x is equal to
	A.  25.6
	B.  16
	C.  10
	D.  12.8

Solution

log32 x =0.8. x=(32)0.8 ‹=›(25)4/5 ‹=›24 ‹=› 16.

4.	The value of log343 7 is
	A.  1/3
	B.  - 3
	C.  - 1/3
	D.  3

Solution

Let log3437 = n. Then, 343n = 7 = (73)n = 7. ‹=›3 n = 1 ‹=›n = 1/3. log343 7 = 1/3.

5.	If logx 4 = 1/4, then x is equal to
	A.  16
	B.  64
	C.  128
	D.  256

Solution

log x 4 = 1/4 ‹=› x 1/4 = 4 ‹=›x= 44 = 256.