NCERT Exemplar Solutions
Class 6 - Mathematics - Unit 1: Number System - Problems and Solutions
Question 171

Question. 171

Find LCM of 80, 96, 125, 160.

Answer:

LCM = 2400

Detailed Answer with Explanation:

Step 1: Write prime factors

\(80 = 2\times 2\times 2\times 2\times 5\)

\(\quad\;= 2^{4}\times 5\)

\(96 = 2\times 2\times 2\times 2\times 2\times 3\)

\(\quad\;= 2^{5}\times 3\)

\(125 = 5\times 5\times 5\)

\(\quad\;= 5^{3}\)

\(160 = 2\times 2\times 2\times 2\times 2\times 5\)

\(\quad\;= 2^{5}\times 5\)

Step 2: Take highest powers of each prime

Prime \(2:\;\max(2^{4}, 2^{5}, -, 2^{5}) = 2^{5}\)

Prime \(3:\;\max(-, 3^{1}, -, -) = 3^{1}\)

Prime \(5:\;\max(5^{1}, -, 5^{3}, 5^{1}) = 5^{3}\)

Step 3: Form the LCM

\(\text{LCM} = 2^{5}\times 3^{1}\times 5^{3}\)

Step 4: Multiply step by step

\(2^{5} = 32\)

\(5^{3} = 125\)

\(32 \times 3 = 96\)

\(96 \times 125 = 12000\)

Therefore, \(\text{LCM} = 12000\).

NCERT Exemplar Solutions Class 6 – Mathematics – Unit 1: Number System – Problems and Solutions | Detailed Answers