Let the principal be P . It's said in the question that the money triples itself in 5 years. So, the amount after 5 years is 3P. So, the simple intrest = Amount - Principal = 3P - P = 2P. Now we know both the principal and simple intrest so we can use the formula of SI to find the answer. ( P * R *Read more
Let the principal be P .
It’s said in the question that the money triples itself in 5 years. So, the amount after 5 years is 3P.
So, the simple intrest = Amount – Principal = 3P – P = 2P.
Now we know both the principal and simple intrest so we can use the formula of SI to find the answer.
( P * R * T ) / 100 = SI
= (P * R * 5 ) / 100 = 2P
= R / 20 = 2P / P
= R = 2 * 20 = 40%
Alternatively , there is a simple shortcut to this.
When the question says the principal becomes n times in T years.
Then , R * T = ( n – 1 ) 100
In this case, R * T = (3 -1 ) 100
= R * 5 = 200
= R = 200 / 5 = 40%
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Let the age of A and B be 4x and 5x respectively. B is 6 years older than A B's age = A's age + 6 years 5x = 4x + 6 5x - 4x = 6 x = 6 So, A's age 4(6) = 24 years
Let the age of A and B be 4x and 5x respectively.
B is 6 years older than A
B’s age = A’s age + 6 years
5x = 4x + 6
5x – 4x = 6
x = 6
So, A’s age 4(6) = 24 years
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