Question

help me in this problem:
f(x) denotes a function defined by sum of the digits of the number x
it is given, f(a)<5
f(b)<5
f(c)<5
find the possible set of a,b,c for which f(a+b+c)>50

Answer 1

what our domain of definition? reals, ints, wholes ....

Answer 2

natural numbers..

Answer 3

the sum of the digits, does that mean: f(a) = 1+2+3+...+a < 5 ?

Answer 4

or say a=23; f(a) = 2+3 < 5

Answer 5

the second one,@ amistre64

Answer 6

natural numbers are positive integers, @ 2bornot2b

Answer 7

n = {1,2,3,...}

Answer 8

yeah, grade 11

Answer 9

i see..

Answer 10

our options for less than 100: a,b,c = {1,2,3,4,10,11,12,13,20,21,22,30,31,40}

this is not all of the ns of course, just the first few that I see that sum < 5

Answer 11

X + 4<-9 = 13 but how do you solve it?

Answer 12

the main problem is f(a+b+c) >50....

Answer 13

@2bor.. at least my school teaches that in class 11 :)

Answer 14

U r in which grade??
and one thing, try out my problem too..

Answer 15

by adding in 1 for 100; we get more:

{110,111,112,120,121,130}

same for 2

{210,211,220}

{310}

just getting a feel for it ;




does f(a+b+c) mean 13+40+1 as: 1+3+4+0+1 ?

or does it mean: 13+40+1 > 50

or: 13+40+1 = 54 = 5+4 > 50 ??

Answer 16

@amistre, the second process, again :)