Question

solve this please
A cuboidal box has height and length as 20 cm and 15 cm respectively. If
its total surface area is 1300 cm² then find the width of the box.
If x and y vary inversely with each other. If x=15 when y=6, then find the
value of x when y = 5.​

Answer 1

Answer:

see the attached file

Step-by-step explanation:

hope it helps mark as brainliest

Answer 2

Question 1:

A cuboidal box has height and length as 20 cm and 15 cm respectively. If its total surface area is 1300 cm² then find the width of the box.

Answer:

Given:

• Height of cuboidal box = 20cm
• Length of cuboidal box = 15cm
• TSA of cuboidal box = 1300cm²

To Find:

• Width of the box?

Solution:

We have given TSA of box with its height and length.

We know that,

TSA of cuboid = 2(LB + BH + LH)

Here,

• L = Length of cuboid
• B = Breadth/Width of cuboid
• H = Height of cuboid

Therefore,

TSA of cuboidal box = 2(LB + BH + LH)

$\large{\implies}$ 1300 = 2(15B + 20B +20 × 15)

$\large{\implies}$ 1300 = 2(35B + 300)

$\large{\implies}$ 1300 = 70B + 600

$\large{\implies}$ 1300 - 600 = 70B

$\large{\implies}$ 700 = 70B

$\large{\implies}$ B = $\small\sf{\dfrac{700}{70}}$

$\large{\implies}$ B = 10

HENCE,

$\large{\boxed{\bf{\pink{Width\:of\: cuboidal\:box\:is\:10cm}}}}$

Question 2

If x and y vary inversely with each other. If x=15 when y=6, then find the value of x when y = 5.

Answer:

Given:

• x and y vary inversely with each other
• x = 15 when y = 6

To Find:

• value of x when y = 5

Solution:

According to question,

$\small{\bf{x~\propto{\dfrac{1}{y}}}}$ [Removing sign of proportion]

$\small{\bf{x~=~\dfrac{k}{y}}}$ [k = constant]

(Putting value of x and y to find value of k)

$\small{\bf{15~=~\dfrac{k}{6}}}$

$\small{\bf{k~=~15\times 6}}$

$\small{\bf{k~=~90}}$

So here, we can see that 90 is constant in this proportional.

Now,

Putting value of y and value of k to find value of x.

$\small{\bf{x~=~\dfrac{k}{y}}}$

$\small{\bf{x~=~\dfrac{90}{5}}}$

$\small{\bf{x~=~18}}$

Thus,

$\large{\boxed{\small{\bf{\pink{Value~of~x~will~be~18~when~value~of~y~is~5}}}}}$