"...challenge where users struggled most to get a perfect score and spent the longest time solving.."

questionMarks.js

function questionsMarks(string) {
  
  let number = pair = count = 0
  
  for (let char of string) {
    
    if ( !isNaN(char) ) {
      
      if (number && number + +char === 10) {
          
        if (count !== 3) return false
        pair = true
      }

      number = +char
      count = 0

    } else if (char === '?') {
      
      count++
    }
    
  }
  
  return pair || false
}