The length of a rectangular blackboard id three times its width. If the width is $1.5 m$ , Find its area . Also find the cost of painting the blackboard at the rate of $R s 5.50 p e r s q . m$

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Solution

Given:Length $= 3 x$ and Breadth $= x$
Width $= 1.5$ m $= 150$ cm
Perimeter $= 2 (l + b)$
$\Rightarrow 150 = 2 (3 x + x)$
$\Rightarrow 150 = 8 x$
$\Rightarrow x = \frac{150}{8} = 18.7$
$∴$ Breadth is $18.7$ m and length is $3 x = 3 \times 18.7 = 56.1$ m
$∴$ Area of the black board $= 18.7 \times 56.1 = 1, 049.07 ‬ m^{2}$
Cost of painting per sq.m $=$ Rs $5.50$
Cost of painting $1, 049.07 ‬ m^{2} =$ Rs $1, 049.07 \times 5.50 =$ Rs. $5, 769.885$

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The length of a rectangular blackboard id three times its width. If the width is 1.5m, Find its area . Also find the cost of painting the blackboard at the rate of Rs5.50persq.m

Given:Length=3x and Breadth=xWidth=1.5m=150cmPerimeter=2(l+b)⇒150=2(3x+x)⇒150=8x⇒x=1508=18.7∴ Breadth is 18.7m and length is 3x=3×18.7=56.1m∴Area of the black board=18.7×56.1=1,049.07‬m2Cost of painting per sq.m=Rs5.50Cost of painting 1,049.07‬m2=Rs1,049.07×5.50=Rs.5,769.885

The length of a rectangular blackboard id three times its width. If the width is $1.5 m$ , Find its area . Also find the cost of painting the blackboard at the rate of $R s 5.50 p e r s q . m$