Select the number that can replace the question mark (?) in the following series.
1500, 745, 370, 180, 87.5, ?
Let's assume 'y' in place of the question mark.
$$y\times2+10 =87.5$$
$$87.5\times2+5 =Â 175+5 = 180$$
$$180\times2+10Â = 360+10 = 370$$
$$370\times2+5 = 740+5 =Â 745$$
$$745\times2+10 = 1490+10 = 1500$$
So $$y\times2+10 = 87.5$$
2y =Â 87.5-10
2y =Â 77.5
y =Â 38.75
Hence 38.75 will come in place of question mark.
Create a FREE account and get: