Hope this isn't too confusing
All of the numbers have different shortcuts.
1. Yes. Divisible by 4: if last two digits are divisible by 4 then the whole number is yes)
2. No. Divisible by 6: it must be even and when you add them up, (44) it must be divisible by 3 (no, 44 is not divisible by 3)
3. Divisible by 8: ( last 3 numbers are divisible by 8 (312) = 39 ( yes it is)
4 Yes. Divisible by 11: ( sum of digits at odd places and sum of digits at even spaces,is either 0 or divisible by 11) yes, 278949. (2+8+9) + (7+9+9)= 19 + 25 = 44 and 44 is divisible by 11)
5. No. Divisible by 12 (divisible by 3 and 4, sum of digits is divisible by 3 ; and last 2 digits divisible by 4: 87654395 : 52/3= 18 (yes) 95/4(no) this number not divisible by 12
6. No. Divisible by 15: divisible by 3 and 5 ..87654385 = 46/3 = 15..(No) divisible by 5 yes. The number is not divisible by 15
Multiply both sides of the second equation by 100 to get rid of the decimals:
0.05<em>n</em> + 0.10<em>d</em> = 1.50
==> 5<em>n</em> + 10<em>d</em> = 150
Multiply both sides of the first equation by -5:
<em>n</em> + <em>d</em> = 21
==> -5<em>n</em> - 5<em>d</em> = -105
Add the two equations together:
(5<em>n</em> + 10<em>d</em>) + (-5<em>n</em> - 5<em>d</em>) = 150 + (-105)
Notice that the terms containing <em>n</em> get eliminated and we can solve for <em>d</em> :
(5<em>n</em> - 5<em>n</em>) + (10<em>d</em> - 5<em>d</em>) = 150 - 105
5<em>d</em> = 45
<em>d</em> = 45/5 = 9
Plug this into either original equation to solve for <em>n</em>. Doing this with the first equation is easiest:
<em>n</em> + 9 = 21
<em>n</em> = 21 - 9 = 12
So Donna used 12 nickels and 9 dimes.
Step-by-step explanation:
2x+3=x+x+3
add the X's on the right side together.
2x+3=2x+3
subtract 2x from both sides
3=3
subtract 3 from both sides
0=0
the statement is true for any value of x
Answer:
The amount of carpet needed in Room Z should be the same as the carpet needed in both Room X and Room Y.
Step-by-step explanatio
