Look at the series: 5.2, 4.8, 4.4, 4, ... What number should come next?

Analyze the number series given below and find the missing number: 256, 364, 472, ?, 688

Select the number-letter cluster that can replace the question mark (?) in the given series: 95MJ, 76KF, 57IB, 38GX, ?

Select the number-letter cluster that can replace the question mark (?) in the given series: 95MJ, 76KF, 57IB, 38GX, ?