All categories

2 years ago

How many 5 digit flippy numbers are divisible by 15.

SAT

1 answer:

marishachu [46]2 years ago

3 0

Answer:

Explanation:

Since it's a flippy number, we can set each digit into ababa

Since it can be divisible by 15, which means it can be divisible by both 5 and 3.

Since it is divisible by 5, the last digit will be either 0 and 5, but it cannot be 0 because 0 cannot be the first digit, so last digit must be 5.

So, ababa --> 5b5b5

It can also be divisible by 3. According to de divisibility rule of 3, if the sum of all digit is divisible by 3 then the number is divisible by 3.

Sum of all digits = 15 + 2b

it's divisible by 3 when b = 0,3,6,9

The answer is 4.

There are 4 such number.

You might be interested in

Factor the expression into an equivalent form 12y^2-75.

elena-14-01-66 [18.8K]

Hello oddworld7836!

$\huge \boxed{\mathbb{QUESTION} \downarrow}$

Factor the expression into an equivalent form 12y² - 75.

$\large \boxed{\mathfrak{Answer \: with \: Explanation} \downarrow}$

$12 y ^ { 2 } - 75$

By observing the expression, we can see that, 3 is the only common factor in both the terms of the expression. So, take the common factor 3 out.

$12 y ^ { 2 } - 75 \\ = 3\left(4y^{2}-25\right)$

Now, look at (4y² - 25). They don't have any common factors but they appear in the form of the algebraic identity ⇨ a² - b² = (a + b) (a - b). Here,

a² = 4, a = 2 (√a² = ✓4 = 2)
b² = 25, b = 5 (√b² = ✓25 = 5)

So, the (4y² + 25) becomes...

$(4 {y}^{2} - 25) \\ = \left(2y-5\right)\left(2y+5\right)$

Now, bring the 3 (common factor) & rewrite the complete expression.

$12 y ^ { 2 } - 75 \\ = \boxed{ \boxed{ \bf \: 3\left(2y-5\right)\left(2y+5\right) }}$

We can't further simplify it. Also, remember that the simplified form of an expression is equivalent to the expression. So, 3 (2y - 5) (2y + 5) is equivalent to 12y² - 75.

__________________

Hope it'll help you!

ℓu¢αzz ッ

8 0

2 years ago

What is the volume of the cone in terms of π? a) 8π in3 b) 16π in3 c) 24π in3 d) 32π in3

Svetlanka [38]

Answer:

Explanation:

What is the radius or diameter? I can't help you without that.

4 0

2 years ago

Why do we want to know how much and type of precipitation?

kicyunya [14]

Answer:

I would assume that we would want to know how much and the type of precipitation to know if the anything is changing within our climate. We would most likely need to know how much precipitation we are getting a year to see if it's less or more the next years to come.

Explanation:

3 0

2 years ago

Newton’s law of cooling states that for a cooling substance with initial temperature t0, the temperature t(t) after t minutes ca

antoniya [11.8K]

The cooling rate of the substance is approximately 0.0732.

According to the statement, the Newton's law of cooling is defined by the following formula:

$T(t) = T_{s} + (T_{o}-T_{s})\cdot e^{-k\cdot t}$ (1)

Where:

$T_{s}$ - Final temperature, in degrees Celsius.
$T_{o}$ - Initial temperature, in degrees Celsius.
$t$ - Time, in minutes.
$k$ - Cooling rate, in $\frac{1}{min}$ .
$T(t)$ - Current temperature, in degrees Celsius.

Please notice that substance reaches thermal equilibrium when $T(t) = T_{s}$ , that is when temperature of the substance is equal to the temperature of surrounding air.

If we know that $T_{o} = 80\,^{\circ}C$ , $t = 15\,min$ , $T_{s} = 50\,^{\circ}C$ and $T(15) = 60\,^{\circ}C$ , then the cooling rate of the substance is: