HELPPP PLZZ I REALLY NEED HELP
2 answers:
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Answer:
See explanation
Step-by-step explanation:
Let x be the number of spade shovels, y -the number of flat shovels and z - the number of square showels sold that day.
The store keeps an inventory of 80 shovels, then
x+y+z=80
The store always buy twice as many spade shovels as square, so
x=2z
The total cost of all shovels is
16x+9.60y+12.80z=1,072
a) The system of three equations is
b) In matrix form this is
c) The determinant is
d) Find three determinants:
So,
e) If the store doubled all prices and inventory, then the new matrix is
Answer:
63%
Step-by-step explanation:
This is a problem of conditional probability.
The two events that are given are:
- Car stuck in the snow - Let it be event S. P(S) = 70% = 0.70
- Require a tow truck - Let it be event T.
We have to find the probability of being stuck in the snow AND requiring a tow truck which can be given as P(S and T)
We are also given the conditional probability, which is P(T | S) = 90% = 0.90
Using the given formula for our case we can modify the formula as:
Therefore, there is 63% (0.63) chance that you will get stuck in the snow with your car AND require a tow truck to pull you out
<span>Ayesha's right. There's a good trick for knowing if a number is a multiple of nine called "casting out nines." We just add up the digits, then add up the digits of the sum, and so on. If the result is nine the original number is a multiple of nine. We can stop early if we recognize if a number along the way is or isn't a multiple of nine. The same trick works with multiples of three; we have one if we end with 3, 6 or 9.
So </span>
<span>has a sum of digits 31 whose sum of digits is 4, so this isn't a multiple of nine. It will give a remainder of 4 when divided by 9; let's check.
</span>
<span>
</span>Let's focus on remainders when we divide by nine. The digit summing works because 1 and 10 have the same remainder when divided by nine, namely 1. So we see multiplying by 10 doesn't change the remainder. So
has the same remainder as 
.
When Ayesha reverses the digits she doesn't change the sum of the digits, so she doesn't change the remainder. Since the two numbers have the same remainder, when we subtract them we'll get a number whose remainder is the difference, namely zero. That's why her method works.
<span>
It doesn't matter if the digits are larger or smaller or how many there are. We might want the first number bigger than the second so we get a positive difference, but even that doesn't matter; a negative difference will still be a multiple of nine. Let's pick a random number, reverse its digits, subtract, and check it's a multiple of nine:
</span>
So </span>
</span>
</span>Let's focus on remainders when we divide by nine. The digit summing works because 1 and 10 have the same remainder when divided by nine, namely 1. So we see multiplying by 10 doesn't change the remainder. So
When Ayesha reverses the digits she doesn't change the sum of the digits, so she doesn't change the remainder. Since the two numbers have the same remainder, when we subtract them we'll get a number whose remainder is the difference, namely zero. That's why her method works.
<span>
It doesn't matter if the digits are larger or smaller or how many there are. We might want the first number bigger than the second so we get a positive difference, but even that doesn't matter; a negative difference will still be a multiple of nine. Let's pick a random number, reverse its digits, subtract, and check it's a multiple of nine:
</span>