Answer:
68 mph
Step-by-step explanation:
80 m/hr * 2 hr = 160 miles
60 m/hr * 3 hr = 180 miles
total miles / total time = average speed
340 miles / 5 hr = 68 m p h
We will set a variable, d, to represent the day of the week that January starts on. For instance, if it started on Monday, d + 1 would be Tuesday, d + 2 would be Wednesday, etc. up to d + 6 to represent the last day of the week (in our example, Sunday). The next week would start over at d, and the month would continue. For non-leap years:
If January starts on <u>d</u>, February will start 31 days later. Following our pattern above, this will put it at <u>d</u><u> + 3</u> (28 days would be back at d; 29 would be d+1, 30 would be d+2, and 31 is at d+3). In a non-leap year, February has 28 days, so March will start at <u>d</u><u>+3</u> also. April will start 31 days after that, so that puts us at d+3+3=<u>d</u><u>+6</u>. May starts 30 days after that, so d+6+2=d+8. However, since we only have 7 days in the week, this is actually back to <u>d</u><u>+1</u>. June starts 31 days after that, so d+1+3=<u>d</u><u>+4</u>. July starts 30 days after that, so d+4+2=<u>d</u><u>+6</u>. August starts 31 days after that, so d+6+3=d+9, but again, we only have 7 days in our week, so this is <u>d</u><u>+2</u>. September starts 31 days after that, so d+2+3=<u>d</u><u>+5</u>. October starts 30 days after that, so d+5+2=d+7, which is just <u>d</u><u />. November starts 31 days after that, so <u>d</u><u>+3</u>. December starts 30 days after that, so <u>d</u><u>+5</u>. Remember that each one of these expressions represents a day of the week. Going back through the list (in numerical order, and listing duplicates), we have <u>d</u><u>,</u> <u>d,</u><u /> <u>d</u><u>+1</u>, <u>d</u><u>+2</u>, <u>d+3</u><u>,</u> <u>d</u><u>+3</u>, <u>d</u><u>+3</u>, <u>d</u><u>+4</u>, <u>d</u><u>+5</u>, <u>d</u><u>+5</u>, <u /><u /><u>d</u><u>+6</u><u /><u /> and <u>d</u><u>+6</u>. This means we have every day of the week covered, therefore there is a Friday the 13th at least once a year (if every day of the week can begin a month, then every day of the week can happy for any number in the month).
For leap years, every month after February would change, so we have (in the order of the months) <u></u><u>d</u>, <u>d</u><u>+3</u>, <u>d</u><u>+4</u>, <u>d</u><u />, <u>d</u><u>+2</u>, <u>d</u><u /><u>+5</u>, <u>d</u><u />, <u>d</u><u>+3</u>, <u>d</u><u /><u>+6</u>, <u>d</u><u>+1</u>, <u>d</u><u>+4</u>, a<u />nd <u>d</u><u>+</u><u /><u /><u>6</u>. We still have every day of the week represented, so there is a Friday the 13th at least once. Additionally, none of the days of the week appear more than 3 times, so there is never a year with more than 3 Friday the 13ths.<u />
Answer:
x = - 5, x = 2
Step-by-step explanation:
Using the rules of logarithms
log x - log y = log (
)
x = n ⇔ x = 
note that log x = 
x
Given
log (x² + 3x) - log10 = 0, then
log(
) = 0, thus
= 
= 1 ( multiply both sides by 10 )
x² + 3x = 10 ( subtract 10 from both sides )
x² + 3x - 10 = 0 ← in standard form
(x + 5)(x - 2) = 0 ← in factored form
Equate each factor to zero and solve for x
x + 5 = 0 ⇒ x = - 5
x - 2 = 0 ⇒ x = 2
Solution is x = - 5, x = 2
First you have to find the slope with the equation y2 - y1 / x2 - x1 , then once you have found the slope (slope = -2) you simply plug it into the point slope formula. y-0 = -2(x-5) solving it algebraically you should arrive at Y=-2x+10. (the 5 and 0 were plugged in are two of the X and Y points of the line which is why we plugged them into the X and Y values of the equation)
Answer:
200 pairs of sandals
Step-by-step explanation:
Represent the sandals with x and the running shoes with y.
In a typical month:
In April
Required
The number of sandals in a typical month
<u>In a typical month:</u>
If 1 sandal costs 2.50, then x costs 2.50x
If 1 running shoe costs 4, then y costs 4y
The total is:
<u>In April:</u>
If 1 sandal costs 2.50, then 2x costs 5x ---- <em>we used 2x because the pairs is doubled </em>
If 1 running shoe costs 4, then y costs 4y
The total is:
The equations are:
Subtract
