Question

WILL MARK BRAINLIEST PLEASE HELP! How many three-digit numbers are multiples of neither 5 nor 7?

Answer 1

 Best Answer

999/7 is just over 142

 

100/7 is just over 14

 

so there are (142 - 14) = 128 numbers that are multiples of 7, hence there are 999-99-128 = 772 numbers that are not multiples of 7.

Answer 2

Hello,
1)
100=20*5999=199*5+4Number of multiple of 5 =(199-20+1)=180
2)100=15*7-5999=142*7+5Number of multiple of 7= 142-15+1=128
3)5*7=35100=3*35-5999=28*35+19Number of multiple of (5 and 7) =28-3+1=26
4) Number of three-digit numbers= 999-100+1=900
5)Number of three-digit numbers are multiples of neither 5 nor 7=900-(128+180-26)=618
Proof :This programm in QB64 print nb=618.

' How many three-digit numbers are multiples of neither 5 nor 7?
DIM i AS INTEGER, nb AS INTEGER
nb = 0
FOR i = 100 TO 999
    IF i MOD 5 = 0 OR i MOD 7 = 0 THEN
    ELSE
        nb = nb + 1
        PRINT nb; i
    END IF

NEXT i
PRINT "nb="; nb
END