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.
1/2r -3= 3 (4-3/2r) is to be solved for r.
I'll begin by making the assumptions that by 1/2r you actually meant (1/2)r and that by 3/2r you actually meant (3/2)r. When in doubt, please use parentheses to make your meaning clear.
Thus, 1/2r -3= 3 (4-3/2r) becomes (1/2)r -3= 3 (4-(3/2)r ) .
Simplify this by multiplying all 3 terms by 2. Doing this will eliminate the fractions:
r -6 = 3 (4*2-(3)r ) or r - 6 = 24 - 9r
Now expand the right side, using the distributive property of
r - 3 = 24 - 9r
Regrouping so as to combine like terms:
10r = 30
Solving for r: r = 30/10 = 3
The value of r that satisfies this equation is 3
Step-by-step explanation:
Add 1 to both sides
Multiply both sides by 4
Take the square root of both sides
Subtract 5 from both sides
(straight from khan academy hints)
Answer:
11+6=17
Step-by-step explanation:
