Question from the Javascript test

What will the following expression return?

[
   { name: 'Lisa', mark: '16' },
   { name: 'Pascal', mark: '13' },
   { name: 'Romain', mark: '12' },
   { name: 'Lucas', mark: '4' },
   { name: 'Aurélie', mark: '14 ' }
]
.map(function(student) { student.mark = Number(student.mark); return student })
.filter(function(student) { return student.mark >= 10 })
.reduce(function(acc, student) { return student.mark+ acc }, 0);