Question
a two figure number is written down at random find the probability
a)that the number is greater than 68
b)the number is a multiple of 9
c) it is less than 100
d) it contains at least one 5 (i.e a number such as 15 or 55
a)that the number is greater than 68
b)the number is a multiple of 9
c) it is less than 100
d) it contains at least one 5 (i.e a number such as 15 or 55
Answers
Steve
There are 90 2-digit numbers
a) 32 are greater than 68, so prob = 32/90
b) 10 are multiples of 9, so ...
c) all are less than 100, so ...
d) 18 have at least one 5, so ...
a) 32 are greater than 68, so prob = 32/90
b) 10 are multiples of 9, so ...
c) all are less than 100, so ...
d) 18 have at least one 5, so ...
PsyDAG
There are 90 two-digit numbers (10-99).
a) 31/90 = ?
b) 18, 27, 36, 45, 54, 63, 72, 81, 90, 99 are multiples of 9.
c) <I>All</I> two-digit numbers are less than 100.
d) 15, 25, 35, 45, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 65, 75, 85, 95 all have at least one 5.
a) 31/90 = ?
b) 18, 27, 36, 45, 54, 63, 72, 81, 90, 99 are multiples of 9.
c) <I>All</I> two-digit numbers are less than 100.
d) 15, 25, 35, 45, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 65, 75, 85, 95 all have at least one 5.
Steve
My bad on (a). PsyDAG is correct
arzam
thanks PsyDAG and Steve
Anonymous
6r