Quantitative Aptitude
SQUARE ROOT AND CUBE ROOT MCQs
Square Roots, Cube Roots, Squares And Square Roots
Sum of decimal places in the numerator and denominator under the radical sign being the same, we remove the
decimal.
`:.` Given exp = `sqrt((.081 xx .484)/(.0064 xx 6.25))` = `sqrt((81 xx 484)/(64 xx 625))`
= `(9 xx 22)/(8 xx 25)` = 0.99
`(3sqrt(12))/(2sqrt(28))` `-:` `(2sqrt(21))/(sqrt(98))` =`(3sqrt(12))/(2sqrt(28))` x `(sqrt(98))/(2sqrt(21))`
=`(3sqrt(4 xx 3))/(2sqrt(4 xx 7))` x` (sqrt(49 xx 2))/(2sqrt(21))` = `(6sqrt(3))/(4sqrt(7))` x `(7sqrt(2))/(2sqrt(21))`
= `(21sqrt(6))/(4sqrt(7 xx 21))` = `(21sqrt(6))/(28sqrt(3))` = `3/4`` sqrt(2)`= `3/4` x 1.414 = 3 x 0.3525 = 1.0605
Given exp. = `sqrt(8) + 2sqrt(32) - 3sqrt(128) + 4sqrt(50)`
= `sqrt(4 xx 2) + 2sqrt(16 xx 2) - 3sqrt(64 xx 2) + 4sqrt(25 xx 2)`
= `2sqrt(2) + 8sqrt(2) - 24sqrt(2) + 20sqrt(2)` = `6sqrt(2)` = 6 x 1.414 = 8.484.
`sqrt(50) xx sqrt(98)` = `sqrt(50 xx 98)` = `sqrt(4900)` = 70.
`3sqrt(5) + sqrt(125)` = 17.88, `rArr` ` 3sqrt(5) + sqrt(25 xx 5)` = 17.88
`rArr` `3sqrt(5) + 5sqrt(5)` = 17.88 `rArr` ` 8sqrt(5)` = 17.88 `rArr` ` sqrt(5) `= 2.235.
`:.` `sqrt(80) + 6sqrt(5)` = `sqrt(16 xx 5) + 6sqrt(5)` = `4sqrt(5) + 6sqrt(5)` = `10sqrt(5)`
= (10 x 2.235) = 22.35
`(sqrt(80) - sqrt(112))/ (sqrt(45) - sqrt(63))` = `(sqrt(16 xx 5) - sqrt(16 xx 7))/(sqrt(9 xx 5) - sqrt(9 xx 7))`
= `(4sqrt(5) - 4sqrt(7))/(3sqrt(5) - 3sqrt(7))` = `(4(sqrt(5) - sqrt(7)))/(3(sqrt(5) - sqrt(7)))` = `4/3` = `1 1/3`
`(sqrt(24) + sqrt(216))/(sqrt(96))` = `(sqrt(4 xx 6) + sqrt(36 xx 6))/(sqrt(16 xx 6))`
= `(2sqrt(6) + 6sqrt(6))/(4sqrt(6))` =`(8sqrt(6))/(4sqrt(6))` = 2
`(sqrt(12) + sqrt(18)) - (sqrt(3) + sqrt(2))` = `(sqrt(4xx3) +sqrt(9xx2)) - (sqrt(3) + sqrt(2))`
`(2sqrt(3) + 3sqrt(2)) - (sqrt(3) +sqrt(2))` = `(2sqrt(3) - sqrt(3)) + (3sqrt(2) - sqrt(2))`
= `sqrt(3) + 2sqrt(2)`.
`(2sqrt(27) - sqrt(75) + sqrt(12))` = `2sqrt(9 xx 3) - sqrt(25 xx 3) + sqrt(4 xx 3)`
= `6sqrt(3) - 5sqrt(3) + 2sqrt(3)` = `3sqrt(3)`
`sqrt(1 + 55/729)` = 1 + `x/27` `rArr` `sqrt(784/729)` = `(27 + x)/(27)` `rArr` `28/27` =` (27 + x)/(27)`
`rArr` 27 + `x` = 28 `rArr` `x` = 1.