All categories

3 years ago

If 18 drinks cost £54, how much will 7 drinks cost ?

Mathematics

1 answer:

Tasya [4]3 years ago

6 0

Answer:

£21

Step-by-step explanation:

Cost of 18 drinks = £54

Cost of 1 drink

= Cost of 18 drinks/18

= £54/18

= £3

Cost of 7 drinks

= Cost of 1 drink × 7

= £3 × 7

= £21

You might be interested in

If f(x) = 3x2 − 8x, 0 ≤ x ≤ 3, evaluate the Riemann sum with n = 6, taking the sample points to be right endpoints.

denis23 [38]

Split up the interval [0, 3] into 6 subintervals,

[0, 1/2], [1/2, 1], [1, 3/2], [3/2, 2], [2, 5/2], [5/2, 3]

The right endpoints are given by the arithmetic sequence,

$r_i=0+\dfrac i2=\dfrac i2$

with $1\le i\le6$ .

We approximate the integral of $f(x)$ on the interval [0, 3] by the Riemann sum,

$\displaystyle\int_0^3f(x)\,\mathrm dx=\sum_{i=1}^6f(r_i)\Delta x_i$

$\displaystyle=\frac{3-0}6\sum_{i=1}^6\left(3{r_i}^2-8r_i\right)$

$\displaystyle=\frac12\sum_{i=1}^6\left(\frac{3i^2}4-4i\right)$

$\displaystyle=\frac38\sum_{i=1}^6i^2-2\sum_{i=1}^6i$

Recall the formulas,

$\displaystyle\sum_{i=1}^ni=\frac{n(n+1)}2$

$\displaystyle\sum_{i=1}^ni^2=\frac{n(n+1)(2n+1)}6$

Then the value of the integral is approximately

$\displaystyle=\frac38\cdot\frac{6\cdot7\cdot13}6-2\cdot\frac{6\cdot7}2=\boxed{-\frac{63}8}=-7.875$

Compare to the exact value of the integral, -9.

7 0

3 years ago

One more rectangular-shaped piece of metal siding needs to be cut to cover the exterior of a pole barn. The area of the piece is

xenn [34]

Answer:

Option A is correct

3.33 ft wide should the metal piece be.

Step-by-step explanation:

Area of rectangle(A) is given by:

$A =lw$ .....[1]

l is the length and w is the width of the rectangle respectively.

As per the statement:

One more rectangular-shaped piece of metal siding needs to be cut to cover the exterior of a pole barn. The area of the piece is 30 ft²

⇒A = 30 ft²

It is also given that the length is 1 less than 3 times the width

⇒ $l = 3w -1$ ft

Substitute the given values in [1] we have;

$30 = (3w-1) \cdot w$

Using distributive property: $a \cdot (b+c) = a\cdot b+ a\cdot c$

then;

$30 = 3w^2-w$

We can write this as:

$3w^2-w-30 = 0$

Factorize this equation:

Split the middle term we have;

$3w^2-10w+9w-30 = 0$

⇒ $w(3w-10)+3(3w-10=0)$

⇒ $(3w-10)(w+3)=0$

By zero product property we have;

$3w-10 = 0$ and w+3 = 0

Since, w cannot be negative;

so,

$w = \frac{10}{3} = 3.3333..$ ft

Therefore, to the nearest hundredth of a foot, 3.33 ft wide should the metal piece be.

7 0

3 years ago

Read 2 more answers

The second side of a triangular deck is 3 feet longer than the shortest side and a third side that is 3 feet shorter than twice

abruzzese [7]

The perimeter of a triangle is:

P = a + b + c

We are given that:

b = a + 3

c = 2 a – 3

Therefore:

68 = a + a + 3 + 2 a – 3

68 = 4 a

a = 17

and,

b = a + 3 = 20

4 0

4 years ago

For an acute angle 0, the equation sin(0) = cos(6) is true. What is the value of ? Show or explain your answer

weqwewe [10]

Answer:

$\theta =84$

Step-by-step explanation:

Given

$sin(\theta) = cos(6)$

Required

Find $\thata$ $\theta$

In trigonometry:

If sin(A) = cos(B), then

$A + B = 90$

So, we have:

$\theta + 6 = 90$

Collect Like Terms

$\theta + 6 -6= 90-6$

$\theta = 90-6$

$\theta =84$

6 0

3 years ago

Lauren read 36 books during the year. If she reads the same number for books for 6 years in a row, how many total books will Lau

katen-ka-za [31]

Answer:

216 Books

Step-by-step explanation:

If she reads 36 books every year, you multiply the amount of books by the number of years. Which, in this case, would be 6 years. So 6×36 is 216 books

6 0

4 years ago

Read 2 more answers