choose the correct formula for minimum my eelovity with which havehical moves in a well of death
Answers
Answer:
Answer:
The breadth of the rectangle is 60 cm
Step-by-step explanation:
Let the length and breadth of the rectangle be ll and bb respectively. since the perimeter of the rectangle is 300cmcm , we have
2(l+ b )= 300\implies l+b=1502(l+b)=300⟹l+b=150
When the length is increased by 20%, the new length is
l+\frac{20}{100}\times l=l+0.2l= 1.2\times ll+
100
20
×l=l+0.2l=1.2×l
When the length is decreased by 30%, the new breadth is
b-\frac{30}{100}\times b = b(1-\frac{30}{100})= b(\frac{70}{100})=0.7bb−
100
30
×b=b(1−
100
30
)=b(
100
70
)=0.7b
The equation for perimeter now is,
\begin{gathered}2(1.2l+0.7b)=300\\\\2.4l+1.4b=300\end{gathered}
2(1.2l+0.7b)=300
2.4l+1.4b=300
Comparing both equations of the perimeter, we have
\begin{gathered}2.4l+1.4(150-l)=300\\\\\implies 2.4l-1.4l+210=300\\\\\implies l=300-210=90 \ cm\end{gathered}
2.4l+1.4(150−l)=300
⟹2.4l−1.4l+210=300
⟹l=300−210=90 cm
So breadth is
b=150-90=60b=150−90=60 cm