What number should be added to each of 4, 16, 18 and 58 so that the resulting numbers will be in proportion in the given order?
Let the number added be = $$x$$
Thus, for the new numbers to be in proportion, we have :
=> $$\frac{4+x}{16+x}=\frac{18+x}{58+x}$$
=> $$(4+x)(58+x)=(18+x)(16+x)$$
=> $$x^2+62x+232=x^2+34x+288$$
=> $$62x-34x=288-232$$
=> $$28x=56$$
=> $$x=\frac{56}{28}=2$$
=> Ans - (A)
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