`(3)/(4) xx" 26% "of " 850=?`

80% "of" 450+20% "of" 850=?

What will come in the place of question mark (?) in the following questions ? 26%" of "520-48%" of "450=?-84

68% "of" 1288+26% "of" 734-215=?

4% of 250 xx ?% of 140=84

26% of 320 - 62.70 + 33.50 =?

31% of 1508 + 26% of 2018 = ?

26% of 640 is "_____"

Percentage of free space in cubic close-packed structure and in body-centred packed structure are, respectively, (1) 48% and 26% (2) 30% and 26% (3) 26% and 32% (4) 32% and 48%