Answer:
x = 1
Step-by-step explanation:
-2x + y = 4
y = 2x + 4
2x + 3y = 20
2x + 3(2x + 4) = 20
2x + 6x + 12 = 20
8x + 12 = 20
8x = 8
x = 1
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
90miles/hour
divide by 360 to convert to miles per second
multiply by 5280 to get to feet per second
multiply by number of seconds to get length (in feet) of each object
Answer:
y = kx
Step-by-step explanation:
In proportional relationships, the value of one variable increases as the other increases or decreases as the other decreases. It is denoted mathematically as y ∝ x where x and y are the variables. It follows that
y = kx where k is the proportionality constant.
So in the relationship where x represents the number of adults, and y represents the number of students,
y ∝ x and y = kx
y = kx is the required equation
Answer:
There are 80 marks in total.
Step-by-step explanation:
Let the number of total marks be 
.
The percentage score of the student can be written as the ratio
.
However,
.
Equating the two:
.
Cross-multiply (that is: multiple both sides by 
, the product of the two denominators) to get
.
.
In other words, there are 80 marks in total.
