Ruby: get sum of nested hash value -

i have hash departments

{"mechnical" => {"boys" => "25", "girls"=>"5"}, "civil"=> {"boys"=>"18", "girls"=>"12"}}   

i want output this,

{"mechanical" => "30", "civil => "30"} 

do below

# if in ruby 2.1 or greater your_hash.map { |k,v| [k, v.reduce(0) { |sum, (_, v)| sum + v.to_i }] }.to_h # => {"mechnical"=>30, "civil"=>30}   # below ruby 2.1 hash[your_hash.map { |k,v| [k, v.reduce(0) { |sum, (_, v)| sum + v.to_i }] }] # => {"mechnical"=>30, "civil"=>30}  # versions your_hash.each_with_object({}) |(k,v), h|    h[k] = v.reduce(0) { |sum, (_, v)| sum + v.to_i } end # => {"mechnical"=>30, "civil"=>30}