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प्रश्न
If 1960 = 2a. 5b. 7c, calculate the value of 2-a. 7b. 5-c.
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उत्तर
1960 = 2a × 5b × 7c
⇒ 2 × 2 × 2 × 5 × 7 × 7 = 2a × 5b × 7c
⇒ 23 × 51 × 72 = 2a × 5b × 7c
⇒ 2a × 5b × 7c = 23 × 51 × 72
Comparing powers of 2,5 and 7 on the both sides of equation, We have
a = 3; b = 1 and c = 2
Hence,
Value of 2-a × 7b × 5-c
= 2-3 × 71 × 5-2
= `1/2^3 xx 7 xx 1/5^2`
= `1/8 xx 7 xx 1/[ 5 xx 5 ]`
= `7/200`
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