How many two digit numbers are there such that the product of their digits after reducing it to the smallest

(this one is 100% right)Explanation:
2 = 12 or 21 So 1×2, 2×1, 3×4, 4×3, 2×6, 6×2, 3×7, 7×3
3 = 13 or 31 So 1×3, 3×1
5 = 15, 51 So 1×5, 5×1, 3×5, 5×3, 7×5, 5×7
7 = 17 or 71 So 1×7, 7×1
15 = 3×5 = 5×3
So total 18 numbers = 12,13,15,17,21,26,31,34,35,37,43,51,53,57,62,71,73,75
so Ans is >>18
8 years agoHelpfull: Yes(15) No(0)
answer is 18
ans the numbers are
12
13
15
17
21
26
31
34
35
37
43
51
53
57
62
71
73
75
8 years agoHelpfull: Yes(3) No(1)
answer is 16

bcs
we know prime no. are 2 ,3 , 5, 7
mulply by 1 is prime no

2 = 21(2*1)=73(7*3)
2 = 21 (2*1)=37(3*7)
2= 12(1*2)=43(4*3)or34(3*4)
.
.
.similarly for all prime no then u will got it....

43 , 34 , 57 , 75 , 53 , 35 ,12,13,15,17,37,73,21,31,51,71

ans is 16 no . only satisfy yhe condition
8 years agoHelpfull: Yes(1) No(8)
ans is only 18
8 years agoHelpfull: Yes(1) No(0)
24 is the right ans
8 years agoHelpfull: Yes(1) No(9)
@shubham i also got 16 but 16 was not in the options. Options were 10,14,18 and 24
8 years agoHelpfull: Yes(0) No(0)
ans is 18.for those who are getting 16 please recheck
8 years agoHelpfull: Yes(0) No(0)
Can someone please tell that why we are not considering 14(1*4=4 = 2^2,18=2^3,19 =3^2)..
8 years agoHelpfull: Yes(0) No(2)
15+51=66
66+66=132
132+321=363
363+363=726
726+627=1353
8 years agoHelpfull: Yes(0) No(2)

How many two digit numbers are there such that the product of their digits after reducing it to the smallest form is a prime number? for example if we take 98 then 98=72, 72=72=14, 14=1*4=4. Consider only 4 prime no.s (2,3,5,7)