Respuesta :
Answer:
The minimum number of letters John has to send to be sure that Peter receives his letter is 127 letters
Step-by-step explanation:
The four digit numbers that are multiples of 5 and 7 with the last digit = 0 is found as follows
Since the last digit of the house number = 10, then the house number is divisible by 10 which also meets the condition that the house number is divisible by 5
We have the four digit numbers from 1000 to 9999
Hence the numbers divisible by both 7 and 10 are from (1000/70 (Which is 14 + 2/7) - 2/7)×70 + 70 = 1050 to (9999/70 (Which is 142 + 59/70)- 59/70)×70= 9940
Which gives 142 - 15 = 127 numbers which are four digit number multiples of 5 and 7 with the last digit = 0
Hence the minimum number of letters John has to send to be sure that Peter receives his letter = 127 letters.
The minimum number of letters that John will have to send to ensure Peter receives his letter is : 127 letters
Applying the given information;
size of house number = Four digits which is a multiple of 5 and 7
House number ends with 0
given that the last number has a 0 digit the house number is divisible by 5 because it is divisible by 10
The Four digit house number will fall between : 1000 to 9999
- Determine the total numbers that are divisible by 7 and 10
( 1000 / 70 ) = [tex](14 + 2/7) - 2/7)*70 + 70 = 1050[/tex]
( 9999 / 70 ) = [tex]( 142 + 59/70)- 59/70)*70= 9940[/tex]
∴ The minimum number of letters of a four digit number that is a multiple of 5 and 7 and whose last digit = 0 will be
142 - ( 14 + 1 ) = 127 letters
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