Question

calculați:
$\frac{a}{10} = \frac{7}{b} \\ \frac{3a}{20} = \frac{3}{b}$
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Answer 1

a/10=7/b

ab=10×7

ab=70

3a/20=3/b

3ab=20×3

3ab=60

ab=60:3

ab=20

Answer 2

ab=7x10. a/10=7/b
ab=70


3ab=20x3
3ab=60
ab=60:3
ab=20