Question

1. find the s.p. when
i) c.p. = ₹20 ; gain = 10%​

Answer 1

Answer:

22 rs

Step-by-step explanation:

Given CP=Rs.20

Gain =10%

⟹SP=CP+gain

⟹SP=20+  

100

10

​  

×20

⟹SP=20+2

⟹SP=Rs.22

Answer 2

Answer:

Given :-

127 2/7 sqcm of sheet is required to make a hemisphere bowl.

To Find :-

What is the length of diameter of the forepart of the bowl.

Formula Used :-

${\red{\boxed{\small{\bold{T.S.A\: of\: a\: hollow\: hemisphere =\: 2{\pi}{r}^{2}}}}}}$

where,

T.S.A = Total Surface Area

Solution :-

Let, the radius be r cm

According to the question by using the formula we get,

⇒ $\sf 2{\pi}{r}^{2} =\: 127\dfrac{2}{7}$

⇒ $\sf 2{\pi}{r}^{2} =\: \dfrac{889 + 2}{7}$

⇒ $\sf 2 \times \dfrac{22}{7} \times {r}^{2} =\: \dfrac{891}{7}$

⇒ $\sf {r}^{2} =\: \dfrac{891}{7} \times \dfrac{7}{2 \times 22}$

⇒ $\sf {r}^{2} =\: \dfrac{891}{\cancel{7}} \times \dfrac{\cancel{7}}{44}$

⇒ $\sf {r}^{2} =\: \dfrac{\cancel{891}}{\cancel{44}}$

⇒ $\sf {r}^{2} =\: \dfrac{81}{4}$

⇒ $\sf r =\: \sqrt{\dfrac{81}{4}}$

➠ $\sf\bold{\green{r =\: \dfrac{9}{2}\: cm}}$

Now, we have to find the diameter of the forepart of the bowl,

As we know that,

$\mapsto$ $\boxed{\bold{\small{Diameter =\: 2r}}}$

Given :

Radius (r) = 9/2 cm

According to the question by using the formula we get

↦ $\sf Diameter =\: {\cancel{2}} \times \dfrac{9}{\cancel{2}}$

➦ $\sf\bold{\purple{Diameter =\: 9\: cm}}$

${\underline{\boxed{\small{\bf{\therefore The\: length\: of\: diameter\: of\: the\: forepart\: of\: the\: bowl\: is\: 9\: cm\: .}}}}}$