diff --git a/solutions/20.js b/solutions/20.js
new file mode 100644
index 0000000..c71d416
--- /dev/null
+++ b/solutions/20.js
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+// Largest Sum in an Array
+// Return the largest sum of 2 consecutive numbers given an array
+// input: [1, 2, 9, 0, 10]
+// output: 11
+
+// Zach Nagatani
+
+/**
+ * Uses a greedy approach to track the largestSum so far, updating as necessary
+ * @param {Number[]} arr - an array of numbers
+ * @returns {Number} largestSum - the largestSum of two consecutive numbers in arr
+ */
+const solution = arr => {
+    let largestSum = arr[0] + arr[1];
+
+    for (let i = 1; i < arr.length; i++) {
+        let currentSum = arr[i] + arr[i + 1];
+        largestSum = currentSum > largestSum ? currentSum : largestSum;
+    }
+
+    return largestSum;
+};
+
+module.exports = {
+    solution
+};
\ No newline at end of file
diff --git a/test/20.js b/test/20.js
new file mode 100644
index 0000000..603c46d
--- /dev/null
+++ b/test/20.js
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+const expect = require('chai').expect;
+let solution = require('../solutions/20').solution;
+//solution = require('../yourSolution').solution;
+
+describe('largest sum in array', () => {
+  it('should return 11 for [1,2,9,0,10]', () => {
+    const result = solution([1,2,9,0,10]);
+    expect(result).to.equal(11);
+  });
+  it('should return 46 for [13,14,32,3,17,6]', () => {
+    const result = solution([13,14,32,3,17]);
+    expect(result).to.equal(46);
+  });
+  it('should work with negative numbers [-1,-2,-9,-3,-10]', () => {
+    const result = solution([-1,-2,-9,-3,-10]);
+    expect(result).to.equal(-3);
+  })
+});