The perimeter of a rectangle is (80) cm and its length is (10) cm more than its breadth. What is the area of the rectangle?
Answer and explanation
Correct answer: 375 square cm
Let the length be
(l
) cm and the breadth be
(b
) cm. Since the perimeter is
80
cm,
2(l+b)=80
, so
l+b=40
. Also,
l-b=10
. Adding the two equations gives
2l=50
, hence
l=25
and
b=15
. Therefore, the area is
l imes b=25 imes15=375
square cm. Thus, option D is correct. 350 square cm would result from not using the correct length and breadth values in the product. Exam tip: first obtain
l+b
from the perimeter, then pair it with the given difference to form two linear equations.
Frequently asked questions
What is the correct answer to this question?
375 square cm
Why is this the correct answer?
Let the length be
(l
) cm and the breadth be
(b
) cm. Since the perimeter is
80
cm,
2(l+b)=80
, so
l+b=40
. Also,
l-b=10
. Adding the two equations gives
2l=50
, hence
l=25
and
b=15
. Therefore, the area is
l imes b=25 imes15=375
square cm. Thus, option D is correct. 350 square cm would result from not using the correct length and breadth values in the product. Exam tip: first obtain
l+b
from the perimeter, then pair it with the given difference to form two linear equations.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Pair of Linear Equations in Two Variables. Topic: Algebraic methods: Substitution method and Elimination method..
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