Respuesta :

sahilsidd

Answer:

a20=a+19d

or,100=a+19d

or, a=100-19d--------(I)

again,

a50=a+49d

or, 400=a+49d

or, a=400-49d--------(ii)

equating equations,we get

100-19d=400-49d

or, 30d=300

so, d=10

Step-by-step explanation:

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