Make Dataframe
df <- data.frame(name = c("Ali","Ahmad","haseeb","Adil","Subhan","Arbaz","Athar","Hassan","Waleed","mehru", "bilal"),
cgpa = c(2.5,3.2,3.9,2.99,3.10,2.99,2.91,2.87,3.2,3.52,3.47),
grade = c("D","B","A","C","B","A","B","B","B","A","A"))
(a) Which students have cgpa greater or equal 3.10
ind <- df$cgpa >= 3.10
ind <- df$name[ind]
ind
## [1] "Ahmad" "haseeb" "Subhan" "Waleed" "mehru" "bilal"
(b) Which students have got B grade
grade <- df$grade == "B"
grade <- df$name[grade]
grade
## [1] "Ahmad" "Subhan" "Athar" "Hassan" "Waleed"
(c) Which student have cgpa > 3 and got A
cgpa_ind <- df$cgpa > 3
grade_ind <- df$grade == "A"
std_name <- df$name[cgpa_ind & grade_ind]
std_name
## [1] "haseeb" "mehru" "bilal"
(d) which student have cgpa > 3 or got A
cgpa_ind1 <- df$cgpa > 3
grade_ind1 <- df$grade == "A"
std_name1 <- df$name[cgpa_ind & grade_ind]
std_name1
## [1] "haseeb" "mehru" "bilal"