Two slits in Young's experiment have widths in the ratio 1 : 25. The ratio of intensity at the maxima and minima in the interference pattern, Imax/Imin is?

Intensity is proportional to the width of the slit. Thus,
I1/I2 = 1/25
or a1/a2 = √(I1/I2) = 1/5
or a2 = 5a1
Now,
Imax/Imin = (a1 + a2)2/(a1 - a2)2 = (a1 + 5a1)2/(a1 - 5a1)2 = (6a1)2/(-4a1)2 = 36/16 = 9/4