How do u solve 31 is 40% of what number? So confused?

1 answer:

6 0

$Method\ \#1\\\\\begin{array}{ccc}31&-&40\%\\x&-&100\%\end{array}\ \ \ \ |cross\ multiply\\\\\\40x=31\cdot100\ \ \ \ |divide\ both\ sides\ by\ 40\\\\x=\frac{3100}{40}\\\\\boxed{x=77.5}$

$Method\ \#2\\\\p\%=\frac{p}{100}\to40\%=\frac{40}{100}=0.40=0.4\\\\x-the\ number\\\\40\%\ of\ the\ number\ is\ 31:\\\\0.4x=31\ \ \ \ |divide\ both\ sides\ by\ 0.4\\\boxed{x=77.5}$

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Step-by-step explanation:

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If two points known on the line AB in the coordinate plane is (7,15) and (18,42), calculate the following..

Ksju [112]

Answer:

Slope = 27/11
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Step-by-step explanation:

Given :-

Two points are given to us .
The points are A(7,15) and B(18,42)

To Find :-

The slope of the line .
The length of line AB .

We can find the slope of the line passing through the points $( x_1,y_1)$ and $( x_2,y_2)$ as ,

$\implies m = \dfrac{ y_2-y_1}{x_2-x_{1}}$

Plug in the respective values ,

$\implies m = \dfrac{ 42-15}{18-7} \\\\\implies \boxed{ m = \dfrac{ 27}{11 }}$

Hence the slope of the line is 27/11 .

$\rule{200}2$

Finding the length of AB :-

We can find the distance between them by using the Distance Formula .

$\implies Distance =\sqrt{ (x_2-x_1)^2+(y_2-y_1)^2} \\\\\implies Distance =\sqrt{ (18-7)^2+(42-15)^2 } \\\\\implies Distance =\sqrt{ 11^2 + 27^2 } \\\\\implies Distance =\sqrt{ 121 + 729 } \\\\\implies Distance = \sqrt{ 850} \\\\\implies \boxed{ Distance = 29.15 \ units }$