Our number system is in base 10, which means that each digit has a value that is a multiple of 10.
For ex:
877 literally means
8 7 7 where each digit is multiplied by
10^ 2 10 ^1 10^0 respectively
which is 8 * 10^ 2 + 7 * 10^1 + 7 * 10^0 = 8 * 100 + 7 * 10 + 7 * 1 = 800 + 70 + 7 = 877
Binary is in base 2, so each of its digits (which can only be 0 or 1) are multiplied by multiples of 2 (2^0, 2^1, 2^2 ect.)
To find what 877 is in binary you can do the following:
the symbol : means divide and i'll write the quotient + the remainder
877 : 2 = 438 + 1 (438 is the quotient, 1 is the remainder)
438 : 2 = 219 + 0
219 : 2 = 109 + 1
109 : 2 = 54 + 1
54 : 2 = 27 + 0
27 : 2 = 13 + 1
13 : 2 = 6 + 1
6 : 2 = 3 + 0
3 : 2 = 1 + 1
1: 2 = 0 + 1
now write ALL off the remainders from BOTTOM to TOP:
1101101101
use a similar step for octal (use 8 instead of 2 as the divisor) and hexidecimal (use 16 instead of 2 as the divisor)
Number of weekend minutes used: x
Number of weekday minutes used: y
This month Nick was billed for 643 minutes:
(1) x+y=643
The charge for these minutes was $35.44
Telephone company charges $0.04 per minute for weekend calls (x)
and $0.08 per minute for calls made on weekdays (y)
(2) 0.04x+0.08y=35.44
We have a system of 2 equations and 2 unkowns:
(1) x+y=643
(2) 0.04x+0.08y=35.44
Using the method of substitution
Isolating x from the first equation:
(1) x+y-y=643-y
(3) x=643-y
Replacing x by 643-y in the second equation
(2) 0.04x+0.08y=35.44
0.04(643-y)+0.08y=35.44
25.72-0.04y+0.08y=35.44
0.04y+25.72=35.44
Solving for y:
0.04y+25.72-25.72=35.44-25.72
0.04y=9.72
Dividing both sides of the equation by 0.04:
0.04y/0.04=9.72/0.04
y=243
Replacing y by 243 in the equation (3)
(3) x=643-y
x=643-243
x=400
Answers:
The number of weekends minutes used was 400
The number of weekdays minutes used was 243
Answer:
A
Step-by-step explanation:
Calculation seems correct to me, with d the distance and h the height of the plane, and i got the same value. Closest value is A tho, so i'd stick with it.
If you want to be pedantic about it, you can always divide the heigth by each value, and get the inverse tangent of each value. With A you get 17.995 which seems the best value you get
